Has anyone actually spoken to them. From what I hear the purpose of AlAnon is to help people so I wouldnt think they would conciously drive others away. Could be the newbies are uncomfortable around the doubles cause they show some of the same traits as the alkies they have at home. Pushyness etc.
I would give them the benifit of the doubt and discuss it with them. Tell them how some of the straight people are not comfortable with the new format. Tell them that youre losing some of the people who need help the most. And ask for their help solving the problem.
Point out that newbies are shy and skittery. Its not the doubles fault, make sure they know that. But since there are two meetings would they consider limiting themselves to just one of the meetings each week. If they need two they can start another for themselves or do a blended meeting for both groups.
Having insight into both conditions Icould see how they could be good guest speakers at an AlAnon meetng but I also can see where they could make the AlAnons uncomfortable. Too much of a reminder of the one you have at home that youre trying to get away from.