Attached Link: edit constrained group: the red vertices will simply follow the doll

Oh, I guess I can post another hotlink by posting another reply. :)

Trac, I suspect that your problem is due to there not being identical vertices in the bikini cloth and its hems, so weld won't do anything.  Bridge (or merge points) will connect them, but you'll need to be able to use a modeler to do that.

Poser 12, in feet.  

OSes:  Win7Prox64, Win7Ultx64

Silo Pro 2.5.6 64bit, Vue Infinite 2014.7, Genetica 4.0 Studio, UV Mapper Pro, UV Layout Pro, PhotoImpact X3, GIF Animator 5