Defining Unity...

In light of our scripture for this week (Matt. 22:36-40 for those of you who have forgotten), I wanted to get your thoughts on "Unity."  There is a great deal of talk these days in the churches around the world, not just COC's, about the need for unity.  The question that I have is how does it actually play out?  Let's take a fictional congregation called "The Way."   Suppose for generations that "The Church" only sang out of hymn books.  One day, a fire burned down a local sister church "The Light," and all the congregants had to meet together at "The Way."  The problem was, "The Light" church always used overheads and felt that hymn books kept them from really expressing themselves.  Now both of these groups were under the same roof, one having a tradition of hymn books, the other a tradition of overheads.  Although neither side could find a support that "proved" they're belief was scriptural, they both felt very strongly about their tradition.  In light of Matt. 22:36-40, and with unity in mind, how should they worship on Saturday (Saturday Sabbath being a tradition they both shared)?  Don't tell me this isn't really a big deal, because to these people it is... So what should they do?  Does unity mean the hymn bookers win because they were there first, so we don't want to rock the boat?  Or does Matt 22 tell us that the over headers should win because they're the neighbors?   Your thoughts please....