Oh Linda I'm sorry to hear about the re-introduction trouble you're having
When I got Bridget she was very dominant and at the time Crystal was my top pig... the initial intro went bad!
I took someone's advice who introduced horses.
Intro the most dominant to the most submissive... I'd give it a good hour then add the next submissive... every hour add another working your way up the more dominant pigs... make sense?
That way the most dominant won't see the majority as a threat... but the top 2 girls will have to figure things out.
This worked for me... but it also took a solid 12 hrs to get all the girls happily tolerating each other on the floor.
I made one whole day for introductions.
Maybe it will help you too!
We'll keep our paws crossed for you and the girls!!
*Expect nipping... expect raised hackles... expect rumblestrutting, expect hair pulling... watch for teeth baring (looks like a yawn)... stand by with dustpan and thick towels ready to break up a full force fight, but I don't think (or at least hope) you won't need it!