Provably Fair, Unknown deck size?

[Venly]

Hi

I am looking at creating some system for a friend. I understand the idea behind provably fair but I am unsure the best method if we do not have a static deck,
e.g.
user 1 puts in a ticket, so far only 8 other tickets have been put in. so user 1 is ticket 9. he can receive a hash but only to shuffle 9.
user 100 puts in ticket 109 but this users deck will shuffle 109
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with the above example user 1 hash will fail as its shuffle will not be the same as user 100. How can I combat this?