Add a Marker in GMap

I've got a new site that's using the D6 GMap module along with Location. It does a nice job of showing me locations of users and nodes, thus far. However, I'd like to show the location of an event (this event is the subject of the entire website) on ALL the GMap's I generate whether for users, nodes, whatever. I only dabble in javascript enough to know that I can add the marker I want using something like this:

      map.addOverlay(new GMarker(GLatLng(40.86997,-92.91825));   // my addition

But where can I put this to add a marker to EVERY GMap the site displays? Or, is there another way to achieve this same effect?

Thanks in advance for any advice you can offer!

Mark