I'm very new to game dev, so take my words with about a kilogram of salt, but it might be better (and cheaper) if you joined a bunch of game jams with the general theme of your game in mind. Or have a few short jams just between your team.
If you do a jam like this you would have to be very clear about your intentions to take inspiration from the jam's submissions for your own game. And there would also be the hassle of finding developers who have the time for it, which I'd imagine would be difficult if you don't already have a reasonably large media presence (granted you might, and this could just be a throwaway account, I really have no idea).
Also, I'm curious about your game. Do you have any screenshots or prototypes that you're able to share?