How can we connect the fifth installment with the previous games in the series?

I have an idea, although it's a bit rough: what if Enroth and Axoth were destroyed by Urgash (see Heroes 5, 6, 7), and before that, they were created by Ashan? As for the old factions from Heroes 3, they could be added to Ashan, since many places in this world have not yet been explored.