This did work out to my advantage once. I submitted to Agent A, forgot all about it, and got an excited call from Agent B. Agent A had said he couldn't handle this particular project, but he thought Agent B would like it. Agent B LOVED it, signed me, and... couldn't sell it, but that's another brush-with-success story for another day.
The point is, Yes, agents can, one way or another, get a manuscript to a colleague if they think it has merit but they themselves aren't right for it or have too much on their plate.