As I've already posted, I'm working up a fantasy tabletop game set in Ancient Rome. I've settled on a date a round 100 BC where the Republic is in it's waning years to be sure, but it isn't exactly in decline as of yet. Magic, as well as exotic creatures, are just now starting to slip into the world but intermittently. To the point that while it is common rumors of strange creatures and events, most people could go their whole lives and not see such fantastical things. The campaign will begin with the local governor (or mayor, haven't decided which) looking for someone to deal with some of the nuisances that are developing as a result. The players will complete a few encounters and after around the second or third game, 


hits the fan. A massive explosion rocks the region from somewhere in the east, and the Party is sent to investigate. What they will eventually discover is that a portal was opened and approximately 20,000 elves (or orcs, haven't decided which yet) were brought over from the other side. In the coming games, there will be attempts to make contact with the new arrivals, but things will be tense as this new group are pillaging the countryside, desperate to feed themselves and (unbeknownst to the players) their families. Eventually, Rome will have to meet this group in force and legion will be summoned to deal with the crisis... one way or the other.
Now, what I'm not so sure is how the game should resolve. I'd like to give the players the option to aid the unwelcomes refugees, or to side with the Romans (all depending on what happens during the course of the game) and I'd like to leave open the possibility of a peaceful compromise. My question though, is how to go about accomplishing this in a way that will bring a satisfactory conclusion as optimially (at least for me if I was player) there would be no end-game battle.




Now, what I'm not so sure is how the game should resolve. I'd like to give the players the option to aid the unwelcomes refugees, or to side with the Romans (all depending on what happens during the course of the game) and I'd like to leave open the possibility of a peaceful compromise. My question though, is how to go about accomplishing this in a way that will bring a satisfactory conclusion as optimially (at least for me if I was player) there would be no end-game battle.