Flat Rate Tracking URL when you may ship by two different carriers

[obewanz]

I'm not sure if this is even doable, but I charge a flat rate for shipping (plus upcharge for specific heavier items) and while this works pretty well (simple is the key word here) I am trying to figure out how to use the tracking url in my carrier when I may ship one order via USPS and another order via UPS.

 

The only solution I can come up with at the moment is to have a second "Flat Rate" carrier with a tracking url for the other possible carrier... but then that sort of defeats the keeping it simple concept.

 

Thoughts??

 

Thanks!