In Dota you have perfect information of the state of all allied units, so I think it's debatable whether sharing input (observation) data between the bots really counts as "communication".
Though that same fact also means communication shouldn't really be necessary; the bots are all exact copies of each other and share a copy of the game state, so they should all have similar ideas of what actions are optimal at any given point in the game.
Though that same fact also means communication shouldn't really be necessary; the bots are all exact copies of each other and share a copy of the game state, so they should all have similar ideas of what actions are optimal at any given point in the game.