We don't have the ability to blacklist specific ubuntu distros for specific packages. 

The ability exists in the spec to blacklist: http://www.ros.org/reps/rep-0137.html#release-build-file however you would have to create separate release build files for each platform to blacklist individually. And that part of the REP is not yet implemented. 

In general we do not want divergent behavior between rosdistros on different Ubuntu distros so supporting this is a low priority.