Mark,

In the Archives, on 2008-03-16,(search for golf 20) there is a question from John about scheduling 20 golfers over 6 rounds, answered by Victoria West. If you take the first three days of that schedule, that's a good start. All you need to do is decide which player numbers correspond to the teams. Looking at the way the schedule is constructed, it seems that making players 1, 2, ..., 10 one team, and 11, 12, ..., 20 the other team, then all should be well.

Have fun!
--Victoria