Does anyone have any suggestions on how to prune a Facebook friends list based on interaction in RR3?

Like a lot of Android (i.e. no Game Center) folk, when I started with RR3 I created a separate FB account just for RR3, and added as many friends as I could, just to rack up those friends bonuses. So my RR3 acocunt nowhas about 1300 friends.

Since the introduction of livery, RR3 is rapidly becoming unusable for me. Switching between series / events causes loooong freezes, presumably while RR3 downloads / sorts out all the friends data. If I log out entirely, or log in with my "real" FB account (with only about a dozen RR3 friends), everything is fine. But when logged in with my "Hugh Mercury" RR3 FB persona ... :(

So, I need to prune my list back, probably chopping it in half. But ... I'd like to keep the folk who actually race. But I just can't think of any way of doing that. Facebook's friend management is severely lacking, and as far as I can tell, there's no way of getting any kind of interaction data out of RR3.

Any suggestions?

Hugh M