Make the dependencies more specific.

Add dependencies on package names and/or specific versions. Use RPM to
examine the package's current "Requires" (both the automatically added
ones as well as manually added ones) and the PHP package's "Provides".

If multiple packages provide the same thing, Yum assumes that either one
can be used to resolve a dependency.

Ok, I hoped yum would not to choose conflicting providers.

Since it does, I suppose I'd better provide 2 separate packages for my app with explicit dependencies.

Thank you for your answer !