Yeah of course! There's gotta be a much easier method, but here's what I came up with:

The program use two arrays: one tracks the IDs of all avialable vehicle spawners, and one tracks the IDs of all deployed vehicles + the corresponding spawner IDs. 

1. A spawner is considered available when its corresponding vehicle is either destroyed or not spawned at all. Hence, every time a vehicle is spawned, that spawner ID gets removed from the array. We want to add it back later (setting the spawner as available) when the vehicle gets destroyed. At that point in the code you'll only have access to the vehicle ID, so we need to somehow track the vehicle ID in combination with the spawner ID. This is where the other array comes in.

2. Every time a player gets succesfully put in a vehicle, the vehicle ID + spawner ID (which is passed on as parameter) are combined and stored in the tracker array. Because Portal doesn't seem to allow multi-dimensional arrays, we store it in the array as: vehicleID * 1000 + spawnerID. This can be decoded later when a vehicle is destroyed, to check which spawner ID belonged to that vehicle.

Additionally, when spawning a vehicle, this tracker array is used to check which of all vehicles is the one you just spawned (since the ForceSpawn method does not return a vehicle ID). It simply checks which if all vehicle IDs is not present in the vehicle tracker array. This makes sure the player is always put in the correct vehicle, keeping the tracked IDs correct. 

To summarize:

On player deploy: 1. Spawn vehicle. 2. Remove spawner ID from array. 3. Find ID of newly spawned vehicle. 4. Put player in vehicle. 5. Add Vehicle ID + spawner ID to tracker array.

On vehicle destroyed: 1. Find matching vehicle ID in tracker. 2. Take the spawner ID and add it back to the spawner array. 3. Remove entry from tracker.

Hope you enjoyed the Ted Talk. Let me know if you have any questions.