[Yum] Yum problem

[John Fox]

I have two servers with the same yum problem. Both have
CentOS4.4 OS. The yum problem is with clamav, clamav-devel,
clamav-db and clamd. I use 3 third party repos, rpmforge,atrpms
and atomic and each have their own versions of clamav etc. When
yum update, yum returns a message on both servers error: missing
dependencies and then quotes the already install version of
clamav. To use yum I have excluded the 4 clamav packages, but at
sometime I will need to update them. Reading through the
archives I have noticed that the same problem has happenned with
other packages, but the solutions tended have not worked. Is
there a way that yum can only accept these packages from one
repo?