When the statistical model behind the GR&R method is understood, then it is possible to extend standard GR&R (one gauge, one facility) to other situations.
The following table shows some of the models available for enhanced Gauge R&R studies.
See also:
GRR Models and EMS Tables (note the documents attached at the bottom of the page)
ASTM E691 "Standard Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method"