How do I make it so someone must be within a certain spawnpoint or a certain distance from a point or spawnpoint or wherever the callout spawns or else it will just cancel itself?

I have 

ShowCalloutAreaBlipBeforeAccepting(new Vector3(-1758.445f, 125.273f, 64.774f), 30f);
            AddMinimumDistanceCheck(100f, new Vector3(-1758.445f, 125.273f, 64.774f));

but it doesn't seem to work as I can be anywhere on the map and it'll still be called and can be accepted.

My callout is basically in the school, which is where the coords are, and I just want to make sure you have to be within like a towns/districs distance or else it dispatch won't call you for it or it'll disregard itself.

if (Game.LocalPlayer.Character.DistanceTo(vector3)>minimumDistance) { return false; }

Semi-pseudocode as I'm not on my dev pc atm for proper syntax etc, but hopefully it should make enough sense.