Hello,
Not sure how much the below information will be useful in your use case
1. You can make that bundle as fragment as i see your use case which will help you not to worry about bundle activation as fragment does not have bundle activator or life cycle
http://wiki.osgi.org/wiki/Fragment
But if you don't want to be fragment then
1. When you create a new bundle in CQ repository you can also define the Activator class (implements BundleActivator) which manages the life cycle of that bundle.
2. It provides two methods start() and stop() with parameter as BundleContext which gives you information related to the bundle.
3. Now based on above information if you can figure out the earlier status of that bundle (Not very sure as i did not try it) it may help you to stop the reactivation of bundle
but i don't think you can stop installation (as installation is different than to its activation)
The best way i can suggest you to manage these through your bundle build process (via eliminating the build of that specific bundle) instead of trying to manage it from inside the bundle
Thanks,
Pawan