20 golfers playing 5 rounds in 4-somes

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Question from joe:

20 golfers playing 5 rounds in 4-somes. 5 players in group A play with all 15 golfers in groups B,C,D but not with any in their own group (A).
5 players in group B play with all 15 players in groups A,C,D but not with any in their own group (B) and so on. So each 4-some has an A,B,C,&D player each of the 5 rounds.
We think we did this successfully about 3 years ago, but can't find the pairings to recreate the format again. I can do it for 16 players but those extra 4 numbers have me stuck. Can you help.
Thank you for being a lot smarter than I am. Joe

Joe,

I think that Penny's answer to Mona seems to work. (It ends after 4 rounds, but it is clear that it can go 5 rounds with the same pattern.)

Chris

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