The Delegate should be declared on the “Sender” Actor and all the “Receiver” Actors can bind to it no matter what Class they are.
You may not want the other classes to include the “Sender” class though for coupling reasons.
If you don’t mind the “Sender” keeping track of who the “Receivers” are then the “Sender” could keep an array of “Receiver” Object Class References and call an interface function on all of them. The “Receivers” need to implement the Interface of course in order to receive the function call.