This is a bit hard to explain, but I'll try. I'm doing som cg/photo composition and I've made an ground plate to receive shadows from the model. The setup is IBL with an environment sphere. I've given the ground plate the attribute "front project target" so that the rotoscope image I use shows and at the same time gets the shadows from the models. however, the plate also receive shadows from the IBL image, that results in a much darker/color burned output than I want. Is it possible to do so that the plate only receives shadows from the model and the models only? what I mean by that is; is it possible to select what objects to receive shadows from?

All I know about is light lists which state which lights light what, and I'm pretty sure that doesn't work with IBL. You could render the background in a sperate render and composite it together using the compositer.