If you are using Profit Accumulator or OddsMonkey they will usually have good advice on these and which way to do them. If the rules don't line up you are looking at Dutching (betting on one outcome at one bookmaker and the opposite at another) which is a bit more advanced than standard MB - tools for this you will also find on the two sites I have mentioned. The retirement rules can be found in the T&Cs of the bookies/exchanges, and you need to check how they will pay out if one of the players retires.