rhel3 / rhel5

Is anyone hosting both rhel3 and rhel5 repos on the same rhel3, or 
rhel5, system?  Do you use the same metadata creation tool on both 
repos?  What yum versions are used on the respective client systems?

Right now our rhel3 clients use yum-2.0.4-1, and yum-arch from the 
same package, for the repo metadata on a rhel3 server.   The rhel5 
clients use yum-3.0-5.4, with createrepo-0.4.4-2.fc6 used to, um, 
create the repo on an rhel5 server.  Is it best to continue to 
maintain these repos separately, hosted on their respective target 
platforms?  I can't seem to resolve dependency issues in trying to 
consolidate on a common metadata tool/client tool.

thanks,
Ed