Would you like to put a note in your families that is just "read only" when used in the project only, like this perhaps?
Create the parameter
Use "Text" for the data type
Enter the value you want stored as text in the formula column
(Just make sure you wrap it with "quotation marks")
If using nested families just make sure you do this in the final host family so you can still "touch" the parameter to connect it to its mate in the host.
Hope this helps!