20 Man, 15 Week Schedule Help

Ok,

So I thought I had this correct, but I actually do have duplicates being created. I don't think the issue is within the actual grid setting each person's partner for the week. That will give each person 1 of the 20 players only once.

And I think the issue is in trying to determine the right number of group pairings to avoid a duplicate.

In the attached you can see what I mean and I have highlighted the 5 duplicates that I seeming, although their could be more I'm not seeing.