How to restrict package installation to x86_64

[John Morris]

Not sure if this is a kickstart, anaconda or yum question, so please 
slap and redirect me if this is the wrong forum.

Our server environment is all x86_64 architecture CentOS 5.1, and thus 
far, new kickstarts have had only a few i386 arch RPMs installed.  
However, now that the nss_ldap package is included in the ks.cfg file, 
it is installed in both x86_64 and i386 architectures.  The i386 version 
brings a bevy of other supporting packages with it.  I wouldn't care 
that much, except that we have a repo of customized packages, all 
x86_64, and don't build for the i386 architecture; however, one of the 
supporting packages that we've upgraded in our custom repo, openldap, 
breaks the install because the original CentOS openldap package of an 
earlier version has file conflicts with our newer version.

In kickstart, is there a simple way to restrict package installs to 
x86_64 architecture only?  Or is there a different, 'correct' way to 
go?  The other solutions I've considered, such as rebuilding our repo 
for i386 or removing all i386 packages from the vendor repos, seem 
hackish and inconvenient.

Thanks-

    John