In a couple of areas where I've had contact with participants, both SPEB members and Adelines referred to the Adelines as "the Ladies Auxiliary of SPEBSQSA."

One or two contest programs in the 50s used the same terminology, where the Adelines were "guest artists."

I don't recall ever seeing any "official" affiliation agreements between the two orgs, and "charters" I've seen don't mention each other.

In the contests I've seen, the competition was limited to male quartets, although both male and female (but not mixed) choral groups usually performed as "bonus entertainment." It's been decades, though, since I've been to a contest.

The Adelines where I knew members were always larger groups, and frequently had sufficient notoriety to have a degree of company sponsorship as "company clubs."

Although I heard rumors that a few SPEB-style female quartets were beginning to appear with some visibility a few years back, I don't know whether they were ever admitted to the SPEB contests. There was, of course, considerable grumbling by the old-line (male) SPEBs about "the insult to tradition, degeneration of morality, offenses to the social order, the destruction of civilization as we know it" but I wasn't close enough to any of those who claimed (pretended?) to be upset to be able to tell whether it was really complaining or just "friendly banter."

John