Three positioned lights brightly moving slowly east over south rim of the Grand Canyon almost dark.

On a camping trip to the North Rim of the Grand Canyon, my son, his girlfriend, my boyfriend and myself saw three lights moving very slowing over the south rim of the Grand Canyon.  We we on the North Rim looking south.  
When we first saw them there were three.  We watched them proceed east in a straight line, very close to the horizon.  
After about 30 minutes, they disappeared one at a time.  First each side light, then the middle one.  The middle one also was at a point of the other two.  
It was a wonderful, neat experience for us.  We never reported it, but after watching so much on the Phoenix Lights, I just had to tell someone.  
They did look exactly like the "Phoenix Lights" appear on television.  They didn't change brightness, blink, or no strobe light appeared as with an airplane.  
Thank you for letting me tell this.  I wish we had had a camera....we didn't.
Witness indicates that date of incident is approximate.  PD