Yep, that's a problem... for me, too.
Here, that copy/paste thing from one session to the next doesn't always work.
Sometimes, in V5Inf v.8, one could leave open the material summary of the preceeding scene,
but that lo longer works in 5.o9, on my Mac.

For the cams, I'd try it the other way 'round : group everything needed, in scene B, save it as one  .vob,
and lod it into a copy of A, where are the cams.
Depends, on what you got in scene B...