We asked our son's individual therapist for a referral - the therapist really encouraged family therapy, and then referred us to someone he knew that was well equipped to help our specific needs.
There was coordination, but it was pretty minimal. These two therapists had clients in common in the past, and knew each other's styles, so even though they probably only talked once or twice (throughout multiple years) the therapy was well aligned goal wise via reporting from parents to either therapist.