First the two parties (area 4 and 5) have to agree to recombine - the BOD is very unlikely to impose that on them and I'm not even sure they have that power anyway. If you want it then lobby the respective REs to get it done not the BOD.
From this thread I can already see some of the stubborness and stupidity that caused the split creeping in. It seemed that compeitors took a back seat to the area officials on this one. I watched this all happen back then and the result was predictable. We have had similar disputes in the SE in both ends of the division and you can work through them without a divorce.
Phil