Group actors into groups and remove them en masse

[Klusimo]

@acxsasx

Store large amount of actors

Load actors into following arrays:

TArray<AActor*> ActorGroup1
TArray<AActor*> ActorGroup2
etc

for (AActor* a : ActorGroup1)
{
a.destroy()
}

Repeat.

Oh so I can use containers for storing pointers to all the actors I need?! Can I use TMultiMap for storing them in specific groups and then removing one key-group when needed?