How Can I tell if a pushpin Exists already at an address?

Is there a way to see if a pushpin exists already at an address? I am cycling through a dataset and want to see if there is already a pin from another dataset in that location.

Also, Is there a property that I can check that tells me the count of pins at a given location???


*note* the pins at the same locations wont have the same names

If there is another way to do this, Id appreciate that as well.
Thanks

Perhaps it might be useful to store the address in the pushpin's note text? That way, not only is the pushpin easily identified to the user, but you can string match pushpins and decide whether or not you want to add it.