I can't figure the ROR in the following scenario: A single zero roulette with 10% rebate on loss in a brick and mortar casino. Four players are betting from a combined BR of 2000 units. They play simultanuously and each of them bets one unit straight up a number per spin (each one bets on a different number). Each one plays until he either win once or lose 20 units, whichever comes first. Each player is claiming his ROL separately.

In that scenario, what would be the ROR of such team? If improper to post, please email me. Thanks in advance, Shark