You are correct. The fields you can select are all fields that appear on the order entry screen somewhere, and that one doesn't.

You can use a report writer such as GridView or Crystal Reports to create your own "Order Action" report for a range of report groups.

Or as a workaround, if you are not using the Price List field for anything else such as maintaining alternate price lists, you can use it in lieu of the Report Group field, and it can be put on the report.

Steve