If these players are all the same person, then it would make no sense to go all in against yourself, as the goal is to get chips from other players.
The accounts will go all against each others when there are no more players left except the accounts.
The strategy can be swapping chips between each others too to make other players weaker in chips.
All depends on the development but the first goal is always keeping all three accounts alive so that they can have the top finishing spots to maximize their profits.