the one thing i did the last time is have 2 sleeping pouches in each cage, a clean unscented one and the one I swap. I started to notice the 4 would sleep in the one with conners scent, and conner would sleep in the one with the other 4's scent. not the clean ones. the intros went great.
BUT, the intro that failed, gus, part of my 6 colony is the alpha and he wouldn't
accept 2 new gliders, he had been fine in other intros, but this last time it was like he said NO MORE. both tries he would fight, big time.
so sometimes you can try several times but if one refuses, there is nothing
you can do.
do the scent training, take your time, and hope they are wanting more family