3 Methods come to mind:
Difference Fx : If you HAVE a bg that is without the individuals in it you can play around with this fx. What it does is to relate any changes ion the RGB pixels and ignore those that HAVEN'T changed. So that IS like a graphics package. I'd put this as a major learning curve!!
Track Motion: This allows for some very quick tweaking. Provides a way to softly edge the join to. I'd put this as a middle learning curve!!
Bezier Curves: Well, this is a "take" on Cheema's Frame and Pan/Crop. But here you DON'T alter the frame but make MASKS to hide that what you don't want. You also "feather" the edges so that there is a more natural blend. I'd put this as the shallowest learning curve!!
Just my thoughts.
If you give me the 2 scenes, as stills, I can knock you up a veg - Vegas7 do? - and post them back. Yeah?
Grazie