Provide a method for assigning group visibility independent of user roles.

We're in the same situation.  We provide managed cloud hosting and have dozens of clients who we are rolling into having customer specific dashboard implementations.  Same bloat ends up happening with alerts as well.  If a customer gets an alert, it interrupts the flow of the alerts to our normal yellow/orange/red  defaults... so if we have to add a single customer specific alert rule, we have to add extras of that for every possible iteration of it in very specific orders with tons of filtering.  It would be nice to have a passthrough / inheritance method on those as well for the same reasons as you're covering for the user permissions.