With that description, no no game option fits.
To be clear, the breakdown is as follows:
Always War - all AI's/Humans are at war with all (other) human players
Always Peace - all AI's/Humans are at peace with all (other) AI/human players
Permanent War or Peace - all AI's/Humans cannot change their war/peace status in the normal way.
Now, there are some exceptions here.
Always War - Peace can be caused through other means (Seven Pines, Corlindale, etc.), but war is always automatically re-declared instantly. AI's can war each other, but rarely do due to shared war bonuses and already having a war ongoing.
Always Peace - War can be caused through other means, but peace is not re-established instantly (if, say, you use a tsunami spell to declare on a nearby player, the war lasts). I don't know if this allows peace to be established in the usual way, though I presume so.
Permanent War or Peace - the same as above. Basically, if you're at war, you can't get out of it (in the normal way) and vice versa, but if you force the change through a variety of ways then that becomes the status quo.
But yeah, no game option fits that if you want them to choose to do it themselves.
Edit: Honestly, I suggest you compromise on something.