Slimdog, yes, you've got it, thanks. However the scale tool is not a replacement because if your geometry is anything more than an extruded profile (say, a 5 1/2" thick wall) that you are scaling only in the direction of extrusion without any holes or niches, you will end up with distorted profile.
Bjoraka, I think I make the best of layers, groups and components in sketchup that I can and it is nothing like how I model in other programs, and I like that. Been using Sketchup for ~4 years. I don't mean to say it's impossible, just time consuming to go through everything and adjust each group affected by the shifted area even with proper naming once you have a fairly well developed model. It's a wish. To be able to select the desired edges from groups that fall within an area selection and then use the move tool on them.