Difficult Relations in the team

Hi,

I have, amongst other teams, one particular group of direct reports that are a challenge. I've recently become their manager after they've had no guidance for over a year. 

Within the group there is one individual that is isolated by the others and there is a lot of bad feeling between the two sides of the camp, basically 2 on one side, 1 on the other and 3 who 'stay out of it'. 

It's obviously not good for performance and I spend my days wishing they'd 'grow up'

All said I appreciate they have had no guidance and really lack confidence in the management structure. I've started rolling out 3o's and getting on top of team meetings and have seen a real improvement, but the relationships within the group are still strained. Given I'm only getting to adding the positive feedback now, has anyone got experience of how to manage individuals that clearly dislike each other? Any tips on the best way to coach them around?

Thanks

J