[CentOS] Dug myself into a hole

I just build a CentOS 6 machine to replace my old machine which broke to where I could not fix it. In attempting to get the applications running which had worked on the old machine, I did updates from several repos such as rpmforge, atrpms, livna, epel, etc. Some of the attempts ended going down blind alleys.

Now I have a mix of rpm's from various sites that I do not need, but they are listed as dependencies of other rpm's.

The rpmforge rpm's are marked with "rf". Is there a process to check which of these rpm's are also in the base libraries and force them back in?

I really do not want to go back to square 1 and reload the system from scratch.

Bob S