Party Story: Three's a Crowd!

I'd like to tell this story, but I can't divulge the characters or their identities.

Let's call it The Party Story! :P
There are three 'parties' here. Party One(P1) is and Party Two(P2) are great friends, have a great rapport for the last few years. P2, have, say fifty members. P1 and P2 have a great time with each other almost every time. P1, a single member, does favors for P2's members quite often than not.

Enter Party Three(P3).
Recently, P3 met P1 and they became best of friends-rather inseparable "friends"!
P2 were feeling slightly neglected due to P1's change of 'heart'; but nevertheless accepted it.
Now, comes the fun part:
This time around P1 has asked a favor, rather major favor, from the members of P2. This favor would be to benefit only P3 and in turn jeopardize P2's comfort.
P2 has to figure out... Yes or No?

What do u think P2 should do???

Find out the rest of the story later when I post it. Till then post in suggestions.

:D