If you want to stick with the lottery idea you could wait till you get all entries before assigning numbers, then say you get 4 entries, you could assign numbers 1-4 in the order in which they were recived, then repeat them, so person would would have 1, 5, 9, 13, 17, 21, 25, 29, 33, 37, and 41. Person would would have 2, 6, 10, 14, 18, 22, 26, 30, 34, 38, and 42. Odds are you would come up with some scrap numbers at the end where you could not repeat a full cycle, I would just leave those numbers out and if it is one of those have a secondary lottery number you would go to. Like first you would go off the first number drawn, if it lands on say 42 and nobody has that number go to the second number drawn.