The attached LV 6.1 code should list all of the VI's in memory and sort by prefered execution system.
It uses a LV reference to get a list of all of the VI's in memory.
The returned array is used to open a reference to all of the VI and then a property node is used to get the "Prefered Execution System" and Priority. These are then bundled along with the VI name and the resulting cluster is accumulated on the edge of a For loop. The array is then sorted and displayed.
I hope this helps,
Ben