Alan was not a group joiner. He had friends in the ex-pat community, like Brian Aherne, but it wasn't a sine qua non for him. Gladys Cooper was a dear friend, but becasue they had worked together in London, not because of being in a group that always hung out together. But he WAS English, after all (at least until 1952) so a lot of people he knew were part of the group. And he DID enjoy cricket, so that sorta forced him to hang out with C. Aubrey Smith.

He and Gip (who had been an actress herself in England, although she was a dental technician here) would have people over for play readings at their home. Some English, some not, but people was had artistic interests beyond the movies.
Boris Karloff was a friend. Val Lewton - not a Brit - a very good friend. Alan gave the eulogy at his funeral.
Alan just liked people in general, but it was Gip who encouraged him to get out more and mingle.