



 
Duane, It is possible, though for each person to play with every other person there would have to be 6 lines. To find the fivesomes, start with number 1, 2, ..., 25 in a 5x5 grid:
Day 1: the rows As you might expect, if there were a sixth day, you'd get the fivesomes by advancing 4 positions each time. I hope this makes sense.  


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