[Konstantinos]

I read before the word "rand", do you set random race checkpoints or you want them by order as they're in the array? Because if that's the case, we'll need to modify it.

https://sampwiki.blast.hk/wiki/OnPlayerEnterRaceCheckpoint

In the above callback, you can check if the player is in a specific race checkpoint (checking a variable you've stored before or checking if the player is in range) and then disable it with:

https://sampwiki.blast.hk/wiki/DisablePlayerRaceCheckpoint