you have several options:
1.- Use a variable such as lastSpawnpoint
2.- Or store spawnpoint.X and spawnpoint.Y as param0 and param1 to pass to a function call.
3- Or use an array if the spawn positions are "fixed" (i.e. you want them to be created at defined positions)
4.- Another one: make the last created spawnPoint sprite have it's variable "IsThisSpawnPointTheLatestOne" set to True (and the others to False), so enemies can only be created there.
5.- Use IID
honestly SC2 makes it very easy :)
If you want to explore any of these just ask :)