What you are missing is that when your calculation refers to a global field, it becomes unstored and unindexed. Such a field can then only be used as a key on the "parent" side of your relationship.
PhilModJunk is the Man! Sorry for making you tell me that twice!
Now that it's working, however, the portal's content doesn't update when the "City, State" global is changed, only after resetting the OrganizationType global. Can I force an update as soon as the global from the foriegn table ("City, State") is changed?
Sometimes a combination of:
Refresh Window [flush cached join results]
is needed to get the portal/layout to update.
You can use a script trigger on the field to perform such a script. If it's a drop down list or edit box, use onObjectExit or OnObjectSave. If it's a pop up menu, radio buttons or check boxes, use OnObjectModify.