you only need to pay 2 gold with a combine RA from 3 cards targeting the abbot?
the abbot + combine attack
A topic from AEG's L5R CCG Rules forum, copied for Oracle of the Void from a copy of the forum saved in October 2015, so pages it didn't save are missing. Players' names are left out; the rules officials are named. Rulings are as they stood on these dates; later rulings, the rulebooks and the Rules Archive may differ.
you only need to pay 2 gold with a combine RA from 3 cards targeting the abbot?
That is correct. You're only targeting him once; the other ranged attacks are interrupting to increase the strength of the one ranged attack.