See the problem with that is that if I make it so that onplayerenterzone > bots > spawn(not the exact events but you get me), everytime another player enters the zone they'll spawn again, and if a player leaves the zone when someone is still in it, the bots will still despawn. Theres prob a work around with oninzone, and a bunch of toggleeventenable and relayevents, but i feel that that is too much and if there was a simpler way it could be done using this mod
What I do to fix that is, on the bot hole its self just put onbotspawn > self > setbottype none (you need to add a delay though otherwise the bots wont go away, so add like a 2 second delay which is 2000).
Then when a player enters the zone the events I do is onplayerenterzone > namebrick(the bot hole) > seteventenabled "0" then afterwords you put in the event to spawn the bot with a delay usually I do 400 onplayerenterzone >namebrick > setbottype default.
Then you wanna have the zone disable its events so can't be activated again. For example
onplayerenterzone > self > seteventenabled 0 1 2 3 4
Usually I name the zones so I can add more then one so no matter what the bots are enabled and you can't bypass the zone.
If you want them to go away after they're killed just do onbotdeath > self > setbottype none
This is how I do my events when it comes to enabling bots, so it should work with you.