From what I know, Bryce isn't set up to do network rendering like, say, 3D Max. What you can do is either set up one for rendering, or split the render job between computers. If you're doing an animation, you could render the bulk on the power house maschine, and the rest on the older one. That way you'll be done at the same time for both machines, and faster than just using one. Also, if it's a single frame, you can split it up between the two and add them together in post (depending on the complexity of the scene). If you can, it most likely will be faster doing it like this, specially if it's a high res job.