Those aren't war goals, for fuck's sakes. It's not about ending the overall conflict. It's about agreeing to terms around the specific war. If one side ceases to be able to operate, then they can agree to terms in order to regain that ability, paying a price for it. The terms would, as I already said, be dependent on the specific situation they're in. The slavers agree to hand over X amounts of slaves and maintain that delivery weekly/monthly for Y amount of time in return for temporary cease-fire/peace as an example.
There's always potential terms, even if the overall conflict can't be solved.