Currently in the modeshape implementation, if object A is modified (e.g. by PATCH) so that it links to object B, two "resource modification" messages are emitted: one for A, and one for B.
It appears that the message for B is nor required by the Fedora spec. First of all, re-visit the logic for emitting B and determine if it still makes sense to emit a message for B.
If a message for B is warranted, then the scope of this task is to determine the contents of the message emitted in response to B. What is most appropriate action? Who are the actors? If agent X modified object A, it seems inappropriate and misleading to fire an event that suggests that agent X also modified object B (i.e. X might not even have permission via B's acl to modify B).