I've got a menu structure such as this

1 About_us
1.1 Physicians
1.2 Locations

Then when a person chooses Doctors, url is going to be www.abc.com/about_us/doctors.html

I wish to change it out to www.abc.com/doctors.html

Any Help?

You may create a concealed menu having a position known as doctors and connect to it in the second-level products of the primary menu.