Hey Rich,
Currently, it seems that species groups are tied back to the Species table. I think it would provide a lot of flexibility to users if groups could be assigned at the calibration level (CalibrationSpecies), since different properties, owners, and regions all group the same species differently. Even allowing multiple groups would be helpful, as sometimes operations, appraisers, and financial groups want different groupings.
Thanks,
Elijah
To add to this, too, I think it would be helpful to limit species options within a stand to those available in the calibration for that stand. That could be too restrictive, but it would make the dropdowns quicker to navigate when you have a large Species table.