Jan - By Modification you mean a Modeller application?

Pluto, Jan - Thank you both; this is exactly what I hoped to do!

I just wish I really understood the principle behind what's going on.  WHen I use the Group Editor, to select what's getting pinned, what am I pinning that cloth to?

Here we are at Frame 5 of my Simulation.  This looks like a nice place to reference where I'd like the cloth slip over her shoulder to.  So, at frame 5, I began my Constraint Group; and then just added the a bit of each side of the collar.  Then I set a Key Frame, went back to Frame 1, and...