I have two websites A.com and B.fm which have two independent Facebook app ids, but I want to merge B into A and make my business approachable by more users (B will have urls like A.com/B/all_b's_original_urls) and B is served in different service (on different server) from A's server, can I make two Facebook ids works on A.com if change B.fm to A.com/B/all_b's_original_urls?
Yes, I can use two facebook app ids for one website. Actually B.fm works as an independent service in A.com, so it doesn't influence A.com at all.