<PAGE>   1
                                                                  Exhibit 10.4.1

         AMENDMENT NO. 1 TO EXECUTIVE SUPPLEMENTAL RETIREMENT AGREEMENT
         --------------------------------------------------------------

     REFERENCE is made to the Executive Supplemental Retirement Agreement (the
"Agreement") dated as of December 2, 1986 between MASSBANK for Savings (the
"Bank"), MASSBANK Corp. (the "Company") and Gerard H. Brandi (the "Executive").

     WHEREAS, the Company and the Bank desire to retain the services of the
Executive, and the Executive desires to continue in the service of the Company
and the Bank; and

     WHEREAS, the parties hereto have agreed to amend the Agreement in
accordance with the terms hereof.

     NOW, THEREFORE, in consideration of services performed and to be performed
by the Executive as well as of the mutual promises and covenants contained
herein, it is agreed to amend the Agreement as of March 1, 1988 as follows:

     1. Articles II and III of the Agreement are amended by deleting said
Articles in their entirety and inserting therefor the following:

                                   ARTICLE II

          2.1 VESTING. The Executive's supplemental retirement and death
     benefits under Articles II and III hereof shall vest in accordance with the
     following schedule: (a) 25% of such benefits were vested as of December 31,
     1987, and (b) an additional 3% of such benefits shall become vested as of
     the last day of each year thereafter if, and only if, the Executive was
     employed by the Company or the Bank for such entire year. For example, if
     the Executive continues as an employee of the Company or the Bank until
     June 1, 1998, such benefits will be 55% vested on such date, and if the
     Executive continues as an employee of the Company or the Bank until


<PAGE>   2


     December 31, 2012, such benefits will be 100% vested on such date. The
     Executive's supplemental retirement and death benefits hereunder shall
     immediately cease to vest whenever the Executive ceases (for any reason
     whatsoever) to be an employee of the Company and the Bank. Except as set
     forth in Section 3.1(a) below, the Executive shall not be entitled to
     receive at any time any unvested portion of any supplemental retirement or
     death benefit.

          2.2 SUPPLEMENTAL RETIREMENT BENEFITS. The Executive shall be entitled
     to receive, commencing on the first day of the month next following the
     later of his termination of employment with the Company and the Bank or his
     65th birthday (the "Commencement Date") and continuing for one hundred
     seventy-nine (179) consecutive months thereafter, supplemental retirement
     benefits equal to the vested portion of his maximum monthly supplemental
     retirement benefit. For purposes hereof, the Executive's maximum monthly
     supplemental retirement benefit is $2,500. For example, if the Executive
     ceased to be an employee of the Company and the Bank on June 1, 1998, he
     would be entitled to receive, beginning on the first day of the month next
     following his 65th birthday and continuing for 179 consecutive months
     thereafter, a supplemental retirement benefit of $1,375 per month.

                                   ARTICLE III

          3.1 DEATH OF EXECUTIVE PRIOR TO COMMENCEMENT DATE. (a) In the event
     the Executive dies while he is an employee of the Company or the Bank and
     prior to the Commencement Date, his beneficiaries as determined under
     Section 3.2 shall be entitled to receive, commencing on the first day of
     the month next following the date of the Executive's death and continuing
     for one hundred nineteen (119) consecutive months thereafter, death
     benefits equal to $3,000 per month; provided, however, that no such death
     benefit shall be payable if the Executive has made any untrue statement on
     an application for a life insurance policy on his life which statement
     causes the Company or the Bank, as the case may be, to fail to receive
     proceeds under such policy upon his death. For example, if the Executive
     died on June 1, 1998 while still an employee of the Company or the

                                        2

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     Bank, his beneficiaries would be entitled to receive on July 1, 1998 and
     continuing for 119 consecutive months thereafter a death benefit of $3,000
     per month.

          (b) In the event the Executive dies after he has ceased (for any
     reason whatsoever) to be an employee of the Company and the Bank and prior
     to the Commencement Date, his beneficiaries as determined under Section 3.2
     shall be entitled to receive, commencing on the first day of the month next
     following the date of the Executive's death and continuing for one hundred
     nineteen (119) consecutive months thereafter, death benefits equal to the
     vested portion of $3,000 per month; provided, however, that no such death
     benefit shall be payable if the Executive has made any untrue statement on
     an application for a life insurance policy on his life which statement
     causes the Company or the Bank, as the case may be, to fail to receive
     proceeds under such policy upon his death. For example, if the Executive
     ceased to be an employee of the Company and the Bank on June 1, 1998 and he
     died on June 1, 2006, his beneficiaries would be entitled to receive on
     July 1, 2006 and continuing for 119 consecutive months thereafter, death
     benefits equal to $1,650 per month.

          3.2 DEATH OF EXECUTIVE AFTER COMMENCEMENT DATE. In the event Executive
     dies after the Commencement Date, but before the payment of all
     supplemental retirement benefits to the Executive has been completed
     pursuant to Article II, the Company and the Bank will continue to pay, in
     lieu of any other death benefits, the unpaid balance of such payments for
     the remainder of the applicable total 180-month period to such beneficiary
     or beneficiaries as the Executive may designate in a written notice filed
     with the Company or the Bank, or, if no such designation is filed, such
     amounts shall be paid to the Executive's surviving spouse, or, if none, to
     his estate. The Executive may change or revoke his beneficiary designation
     from time to time by filing a written notice to that effect with the
     Company or the Bank.

                                        3


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          2. As so amended hereby, the Agreement remains in full force and
     effect and shall continue to be binding upon the parties thereto.

     IN WITNESS WHEREOF, the undersigned have signed, or caused their duly
authorized officers to sign, this Amendment as of March 1, 1988.


                                   MASSBANK FOR SAVINGS

                                   By: /s/ John H. Wood, Chief Executive Officer
                                       -----------------------------------------

                                   MASSBANK CORP.

                                   By: /s/ John H. Wood, Chief Executive Officer
                                       -----------------------------------------

                                       /s/ Gerard H. Brandi
                                       ------------------------
                                       Gerard H. Brandi

                                        4

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                                                                  Exhibit 10.4.1


                                 AMENDMENT NO. 2

                                       TO

                   EXECUTIVE SUPPLEMENTAL RETIREMENT AGREEMENT
                   -------------------------------------------

     REFERENCE is made to the Executive Supplemental Retirement Agreement (the
"Agreement") dated as of December 2, 1986 between MASSBANK for Savings (the
"Bank"), MASSBANK Corp. (the "Company") and Gerard H. Brandi (the "Executive"),
as amended by Amendment No. 1 thereto.

     WHEREAS, the Company and the Bank desire to retain the services of the
Executive, and the Executive desires to continue in the service of the Company
and the Bank; and

     WHEREAS, the parties hereto have agreed to amend the Agreement in
accordance with the terms hereof. NOW, THEREFORE, in consideration of services
performed and to be performed by the Executive as well as of the mutual promises
and covenants contained herein, it is agreed to amend the Agreement as follows:

     1. Section 2.2 of the Agreement is hereby amended by deleting said Section
in its entirety and inserting therefor the following:

          "2.2 SUPPLEMENTAL RETIREMENT BENEFITS. The Executive shall be entitled
to receive, commencing on the first day of the month next following his
termination of employment with the Company and the Bank (the "Commencement
Date") and continuing for one hundred seventy-nine (179) consecutive months
thereafter, supplemental retirement benefits equal to the vested portion of his
maximum monthly supplemental retirement benefit. For purposes hereof, the
Executive's maximum monthly supplemental retirement benefit is $2,500. For
example, if the Executive ceased to be an employee of the Company and the Bank
on June 15, 1998, he would be entitled to receive, beginning on July 1, 1998 and
continuing for 179 consecutive months thereafter, a supplemental retirement
benefit of $1,375 per month."


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                                        I

     2. Section 3.1(b) of the Agreement is hereby amended by deleting said
Section in its entirety and inserting therefor the following:

          "(b) In the event the Executive dies after he has ceased (for any
reason whatsoever) to be an employee of the Company and the Bank and prior to
the Commencement Date, his beneficiaries as determined under Section 3.2 shall
be entitled to receive, commencing on the first day of the month next following
the date of the Executive's death and continuing for one hundred seventy-nine
(179) consecutive months thereafter, death benefits equal to the vested portion
of $2,500 per month. For example, if the Executive ceased to be an employee of
the Company and the Bank on June 15, 1998 and he died on June 20, 1998, his
beneficiaries would be entitled to receive on July 1, 1998 and continuing for
179 consecutive months thereafter, death benefits equal to $1,375 per month."

     3. As so amended hereby, the Agreement remains in full force and effect and
shall continue to be binding upon the parties thereto.

     IN WITNESS WHEREOF, the undersigned have signed, or caused their duly
authorized officers to sign, this Amendment this 28th day of April, 1994.


                                                     MASSBANK FOR SAVINGS

                                                     By: /s/ Reginald E. Cormier
                                                        ------------------------
                                                        Treasurer


                                                     MASSBANK CORP.

                                                     By: /s/ Reginald E. Cormier
                                                        ------------------------
                                                        Treasurer


                                                     /s/ Gerard H. Brandi
                                                     ------------------------
                                                     Gerard H. Brandi

<PAGE>   7

                                                                  Exhibit 10.4.1


                                AMENDMENT NO. 3
                                       TO
                   EXECUTIVE SUPPLEMENTAL RETIREMENT AGREEMENT
                   -------------------------------------------


     REFERENCE is made to the Executive Supplemental Retirement Agreement (the
"Agreement") dated as of December 2, 1986 among MASSBANK (the "Bank"), MASSBANK
Corp. (the "Corp.") and Gerard H. Brandi (the "Executive"), as amended by
Amendments No. 1 and No. 2 thereto.

     WHEREAS, the Company and the Bank desire to retain the services of the
Executive, and the Executive desires to continue in the service of the Company
and the Bank; and WHEREAS, the parties hereto have agreed to amend the Agreement
in accordance with the terms hereof.

     NOW, THEREFORE, in consideration of services performed and to be performed
by the Executive as well as of the mutual promises and covenants contained
herein, it is agreed to amend the Agreement as follows:

     1. Section 2.1 of the Agreement is hereby amended by deleting said Section
in its entirety and substituting therefore the following:

          "2.1 VESTING. The Executive's supplemental retirement and death
     benefits under Articles II and III hereof shall vest in accordance with the
     following schedules: (a) 25% of such benefits were vested as of December
     31, 1987, (b) an additional 3% of such benefits shall become vested as of
     the last day of each year thereafter, and (c) 100% of such shall become
     vested as of December 11, 1996.

     2. Section 2.2 of the Agreement is hereby amended by deleting the last
sentence of said Section.

     3. Section 3.1(b) of the Agreement is hereby amended by deleting the last
sentence of said Section.

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Page 2


     4. As so amended hereby, the Agreement remains in full force and effect and
shall continue to be binding upon the parties thereof.

     IN WITNESS WHEREOF, the undersigned have signed, or caused their duly
authorized officers to sign, the Amendment this twenty-first (21st) day of
January 1997.

                                              MASSBANK

                                              By: /s/Reginald E. Cormier   
                                                 ---------------------------   
                                              Title: V.P.,Treasurer, and CFO




                                              MASSBANK CORP.



                                              By: /s/Reginald E. Cormier   
                                                 ---------------------------   
                                              Title: V.P.,Treasurer, and CFO