How to create a scenario with different win conditions

I have this scenario idea, where you have a player on each side of the map, and the only way into each players base, is up a long hill. With plenty of resources in each players area.

In each players base, they have a little tent, which spawns their king, and a little tent of the enemy team.

The aim of the game is to get your king, inside the tent of the enemy's base. Each time your king dies he reswpans back in your own base out of the little tent.

Thought it would be a fun little game, as it could be really difficult trying to fight uphill, clearing a path which is safe enough for your king to run through and win the game.