After a bunch of research and a few hours of shopping for parts I finally figured out how to replace the cheap little tin grill that came with my Flagstaff 23LB with a better Coleman XLE grill.
Several discussions are posted on various RV forums that this is very difficult to do and one person made a home made hose and connected it using hose clamps. I didn't like that idea.
Here are some photos of my setup and I posted a video on Youtube as to the parts needed and how I did it.
The Youtube video can be found at: