Evan,

There are exactly 20 ways to choose groups of three from your 6 golfers, which means that in TEN rounds, all possible pairs of threesomes would be used exactly once, so that each pair of golfers would play together in exactly four rounds. The best you can do in only 8 rounds is to drop two of the ten possible rounds, which necessarily will mean that some pairs will play together only twice, while others play together three or four times. Here is a systematic list of the twenty threesomes. For your eight rounds together, just delete any two rows of the table; for example, if you delete the final two rows, the pairs 1&6 and 2&3 will play together only twice.

Chris