I found this blog the other day, The Assembling of the Church (which, by the way, is a cool name), and it seems like a pretty good one. At the link there, you will find an article on Church Unity and discipline:
When I put these thoughts together, something occurs to me. Unity is necessary if discipline is going to be a deterrent from divisiveness (or any other unrepentant sin). Think about that for a moment. In order for discipline to be effective, there must be unity. Perhaps this is one of the reasons that we rarely see discipline today: discipline doesn’t work because there is no unity to begin with. Of course, this is just one reason that the church should live in unity. There are many, many more reasons.
There does come a time for separation, indeed, but there are times that separation can lead to Unity. Anyway, enjoy the link.