Client-sided or server-sided?
If you want client-sided methods:
1. Take a look at the NPL_List object. Try dumping it's functions and figure it out.
2. You can only do this if you are in the mini-game yourself. Try looking at the mini-game GUI's owners list, player list for Super Admin status and, again, player list for in-your-mini-game colors.
If you want server-sided methods:
1. Loop through members of the clientGroup object.
2. You can refer to a client's mini-game through the .miniGame field. Mini-Games also have a .owner field which refers to the client running the mini-game. Figure it out from there.