Site Columns are just metadata (definitions of data types); they don't
represent the actual data.

Would a Lookup field do what you want? You can use it in one list  to point
to an item in another list.

Site columns  provide a centralized place for storing the DEFINITION of a
column that can be used in any list. That doesn't mean that data stored in
the columns is synchronized. There is no way out of the box to synchronize
the contents of two different lists  even if they have the exact same schema
definition. Synchronizing information  in sharepoint  requires either custom
code or purchase of a 3rd party application.

that was the information  I needed in order to understand why it
wasn't doing what I thought it should do. I appreciate that! Such limitations
- I cannot use 3rd party software unless I buy the hosting server's pricy plan
upgrade. I had considered running the sharepoint  services off our own server,
but there is all the maintenance problems and learning  curve to fight, and we
lose power alot where we are.
As for lookup fields, I will see how far that will get me