How do I stop a sprite to spawn another sprite?

So I've managed to have a sprite spawn itself again after a drag and drop. The problem though, is that the drag and dropped sprite can spawn another one like it just did and this can keep going infinitely. How do I disable it from spawning another one, while still having the base sprite have the ability to spawn more when selected?

I've attached a capx.

I've posted this a few times before.. hope it's suitable for you.

[attachment=1:7s2g3ck5][/attachment:7s2g3ck5]

This is even simpler but it replaces the 'origin' object each time, which might not be suitable.

[attachment=0:7s2g3ck5][/attachment:7s2g3ck5]

Thank you so much codah! This really opened doors with what I can do.