My advice to the non blackmailed Royals is to get my cooperation then 'own up' to what's been happenning. Yes the guilty will be shamed both blackmailer and blackmailed and senior Royal heads will metaphorically roll but with my support, I believe you (the Monarchy) will survive but wait until they the blackmailers (who I hate) spill the beans and I will be in no position to deny what they are saying is true, which (anyone with foresight) should be able to see could kill the Monarchy!
In this case attack is better than defence, as Andrew has proved you can't defend against these people. You have to take down these dangerous blackmailers no matter what damage it does to the Monarchy. Your biggest asset is William and Kate, not only are they not involved in this mega scandal but like me they are victims of it (Diana).
It always looks worse if you try to defend the indefensible. Own up, take it on he chin, then start attacking these evil blackmailers!