Complex sentence: The Holy Catholic Church-Anglican Rite (HCC-AR) separated from both of these in 1997, then in 1999 itself divided into the Holy Catholic Church-Anglican Rite and the Holy Catholic Church-Western Rite.
Split into simpler sentences: The Holy Catholic Church-Anglican Rite (HCC-AR) was created by a separation from from both of these in 1997. Then in 1999 it divided into the Holy Catholic Church-Anglican Rite and the Holy Catholic Church-Western Rite.