I'm trying to create a small league. The league would have between 6 and 20 teams. I've been trying to create a function that would create fixtures whereby teams would play all others once only in different Rounds. I've created the 1st round with a Do Until loop but after that I'm having problems. Has anybody else done this or have any idea how to create the function?

1 v 2
3 v 4
5 v 6
7 v 8

1 v 3
2 v 5
4 v 7
6 v 8