I agree, it's an interesting question! Once again, we're discussing a "tricky" battle on this map, and I haven't gotten to it yet. Maps where each battle requires its own winning tactic, and finding it isn't always easy, are rightfully respected by players, showing that even in single-player against the AI, there can still be interesting battles (for those aces who have "seen it all"! ;)).
In this situation, if the blue hero has Berserk and expert fire magic, and if his turn is first (perhaps one of the opponents has artifacts that increase speed?), you could try positioning the Djinns so that the Cerberi cluster together, and in the next round, use Berserk to capture most of the stacks. But the problem is that the Cerberi are two-hex creatures, and you can't "beautifully" cast spells on all of them at once.
So, I also ask: please upload the save file, so we can experiment! Or at least tell us: which heroes have which skills, schools of magic, spells, and artifacts?
Another question: as far as I remember, the player starts with Stronghold, then captures Rampart, Fortress... Why does he now have Tower troops? Where did the Rust Dragons come from?