Feature Request - Cascading message deletion

Please give us an option to allow roles to manage messages only for those roles lower than them on the permission hierarchy.

So Admins can delete anyone, Role1 can delete Role2+ but not admins, Role2 can delete Role3+ but not Role1/admins, etc..

It would make things a lot nicer in this time where hostile takeovers are prevalent to be able to limit permissions like this.