RPM meta package

I have a package which previously depended on postgresql92-odbc, but I 
would like to be able to upgrade that without explicitly changing the 
dependency, for all future versions.  Maybe something like "depends: 
postgresql-odbc > 9".

The various postgresql-libs RPMs provide this - i.e., I can install 
postgresql94-libs and it satisfies any dependency for postgresql-libs. 
But the only RPM that satisfies the dependency for postgresql-odbc is an 
old one:

> yum provides postgresql-odbc
postgresql-odbc-08.04.0200-1.el6.x86_64 : PostgreSQL ODBC driver
Repo        : base

Is there some reason that postgresqlxx-odbc RPMs don't provide the 
virtual package for postgresql-odbc, so that whatever version I have 
installed will fulfill the dependency?

Thanks,
Jeremiah