Hi Rich,
Based on your latest reply, Please try to create a new customized authorization object by using t code RSSM instead of using SU21.
Here Salesorg field is by default Organizational field.
Steps to create BW Auth objects.
1. Please make sure characteristic value (0salesorg) is authorization relevant or if not make that one as "Authorization Relevant" under Business Explorer tab of RSD1 t code.
Note: if you are using customized sales org by copying standard characteristic value of Salesorg then make sure to maintain that value as Auth Relevant.
2. Go to RSSM and Specify the name of Customized auth object and click on create.
3. Select the sales org char value from right hand side pane and move it to left hand side.then save the Object.
4. Add the newly created auth object in to required roles then Sales org field by default will be appeared as organizational field from there you can derive the as per your requirement.
I hope this will helps to your requirement.
Thanks,
Siva