Complex sentence: The IRFU also insisted on International team squad training sessions taking precedence over Celtic League matches--a consequence of this was that Irish provinces (especially Munster and Leinster) often fielded virtual second teams for Celtic League games.
Split into simpler sentences: The IRFU also insisted on International team squad training sessions taking precedence over Celtic League matches. A consequence of this was that Irish provinces (especially Munster and Leinster) often fielded virtual second teams for Celtic League games.