Render in layers

Is this possible in Blender? I would need to get sertain objects in a sceene rendered of a different layer in my animation, couse I want to apply greater motionblur to them than to the others objects, and I cant just render out the objects in two different renders whith alpha channels and then composite them because the object I want to have more motionblur on sometimes infront and sometimes behind the other objects and it would be a serious pain in the ass to make layermasks in each frame…
Hmmm… I wonder if i managed to explain what I need, reading what I just wrote I can see that my explination is kinda hard to understand. (Somehow I often have a hard time understanding my self:) ) Anyway I hope you understand me and can help me find a solution.

I’m not sure but you could try creating new scenes and link the objects you want to group together to these scenes. Arrange them in the sequence editor and apply different settings to their render output (at least I THINK that is possible, it works for post-processing so I think it works for renders also).

I’m not sure that was what you were looking for, but give it a try.

You can do it by layering the scene for composition later. You have layers in blender but they don’t render in pieces, you’ll have to select the layers and render, then repeate.