The thing is that when superpowers join in and they bring in their grunts over local conflicts, the wars aren't fun any longer, both IC and OOC. Is there any way Melhed can survive a combined assault? No and soon the continent would go back to the boring peace.
The players in other realms aren't required to ensure that you are sufficiently supplied with your brand of fun.
If what they are doing is objectionable to you, and presumably to other people involved in the war, then take IG action to remove them from the war. if they are intervening on your side, then tell them to get lost because you do't want help. If they refuse, then maybe band together with your enemy in a temporary truce to fight off the interlopers. If they are intervening on the enemy's side, talk to your enemy and see if that is still an available option. Talk to your allies about getting support, either diplomatic or military, to discourage them from joining in.
If no one is willing to intervene to discourage the action you don't like, then maybe you're the only one who doesn't like it, and the "Greater Fun" is being served by what's happening.
