Ok here's a pretty dirty way to do it:
So basicly it says: when a certain event is triggered (in this case a button is clicked), it sets a group active and in that group it generates a random number between 317 and 700 at every tick. Then it checks in the subevent if that number does NOT lie between oldLocation-100 and oldLocation+100 (meaning: it does NOT lie within range of 200px of the oldLocation). So if that's the case, it sets that good number as newLocation AND oldLocation, generates an object at that location and sets the group inactive. Until you click the button again.
I'm sure the more experienced guys here can provide you with a better solution because this is probably not that good performance-wise.