Grits,
It's a little hard to envision your second intersection description, but perhaps you will find some helpful information on one of these pages:
http://bicyclesafe.com/
http://www.bikexprt.com/streetsmarts/usa/chapter3a.htm

You should do whatever it takes to stay safe when negotiating intersections. It sounds to me like your friends have put convenience ahead of safety. They should NOT be riding between two lanes of traffic in order to move ahead of the cars at an intersection, hill or no hill. Eventually some car will suddenly decide to change lanes and will turn right into them because the driver was not expecting a bike to be riding where there was no lane. It won't much matter who had the right of way, but you know who will be the more injured between car driver and bike rider.

Stick to your guns and stay safe.

I always act just like a car as I move through an intersection. After passing through safely, I return back to my regular 'bike position' on the right side of whatever lane I'm riding in and allow cars to pass me freely.