Not the best graphic, maybe this will be better.
Does this help? The zones at the top and bottom are the purple zones, in the middle is the red zone.
Players will spawn as 2 groups, 1 group in the top part of the map and 1 in the lower part
They will race to the line on their part of the map where their purple zone meets the red zone and caste their icarus within their purple zone.
They will then proceed to escort their icarus through the red zone into the other teams purple, winning the game.
Players can enter into the red zone and attempt to caste spells ahead of their icarus, but doing so may be dangerous if the other player(s) fail to caste their team's tower, because no icarus can be cast within the redzone.
It seemed like a simple idea but there's some necessary framework required up front to make sure all the players are playing the same game. Even if 2 or 3 of us get it, it'll be simpler to convey during gameplay if need be.