Inter-party conflict can be interesting when it's in character. If it bubbles up at any point, act to enhance the need to work together by throwing the arguing parties into a desperate situation. Enemies attack, or they trigger a trap, or are stuck somewhere dangerous. Bonus points if you can make it look like the fault of someone in the party.

Transcript

Han: No, wait 3PO. That won't work at all. There are troops out there.
Darth Vader: {over radio} Good job, my daughter. Delay them just a moment longer.
Leia: Look guys, you gotta believe me, I'm no traitor! Hurry up and get us out of here!
GM: They're setting up a heavy gun.
Han: I shoot at them first!
[SFX]: Pow! Kaboom!
[SFX]: Pow! Pow!
C-3PO: Not to drive a wedge between anyone, but we need to resolve this now. All in favour of kicking Princess off the ship?
Leia: What?!
C-3PO: I vote she stays.
Chewbacca: I concur fully. It would be most unchivalrous to leave a Princess out in the cold.
Han: Well, maybe if she could just push the ship a bit...