Socialise....with my local FoE group?

Not likely.
The thread is about celebrating success with your group, rather than just socialising.
In the Amnesty group I used to run, we combined celebrating, campaigning, socialising
and fundraising by holding music nights at the end of, or as part of, campaigns. It's just a matter of hiring a venue like a pub and putting on a few acoustic acts. Quite straight forward stuff.
You can charge a couple of quid for entrance, get people to sign campaign postcards and letters while they are there, have a drink with your group, and recruit people on the night. On one night we raised 700 quid and got 3 new members.
Hx