For the love of god any conversation of import needs to drag the whole party in and decisions should be a thing where the most able person (or whomever the party chooses) says or does a thing. That is HOW a DnD party works. THe charismatic person talks to the guard, not the brain dead fighter because he walked into the room first and no one in the party is even aware they are talking.
SO yeah, dialogues involving everyone and letting the most able person (or whomever the party allows) to do things. Heck could be as simple as the vote system now, where say I select an option and the other two select my face that appears to agree to let that answer/action go.
PS: I just realize I recognize you from the forums during div 2 EA. Heya :O