My team is going to add a new RPM, Y, to the user land. There has been an RPM, X, which has to be mutually exclusive with Y. In other words, X and Y must not coexist.
Thus, in the spec file of Y, there is a line saying "Obsolete: X."
The thing is that we cannot modify the spec file of X. When it was written, there was no such package named Y. Thus, it neither "Obsoletes" nor "Conflicts" Y.
We may add more fake/virtual/meta packages to the user land. Is there anyway that the existing package X also effectively obsoletes the new package Y?
yum install X
must remove Y if it is installed.