A medium isn't super large. You need to fit what ever you do into the BGE. The most likely solution:
Grill in normal positon
Pizza stone on grill
Pie tin (upside down) on top of pizza stone
Pork in what ever on top of the pie tin.
The I have a nasty feeling that's going to be to tall to fit...
Alternative if it is:
Grill in normal position
Cut up coat hangers holding the pizza stone about 2" below the grill
Pork in what ever on top of the grill
That should fit, the trick will be getting the coat hangers bent up so the stone does not drop.