Randy,
I do like how you actually used the Selection field to auto populate the other 4 parameters. Using that logic, do those 4 parameters have to be visible then? I would assume that if they get auto populated from a table, then that should be the correct input and the user wouldn't have to make any corrections. So something like this
User selects One in the Selection parameter and then the other 4 parameters (not visible to the user), get populated with A1, A2, A3, and A4 respectively? And then used in the script tool.
As for my workflow that I originally intended for, there would only be 4 parameters. So the tool window will look like this:
Then there would be the following table in the database:
The idea is to get the tool (using validation) to link the table and the 3 fields (AsBuiltType, AsBuilt Company, and ConstCompany; AsBuiltDate will be a manual entry) to be linked to Document Type, Document Company, and Construction Company. So this is the order they'd be paired (field name - Parameter): AsBuiltType - Document Type, AsBuiltCompany - Document Company, and ConstCompany - Construction Company. The idea is that the drop down menu (value list) will get populated with the values in that field. This is so that when a new company's name is added to the table, the drop down menu doesn't have to be manually updated, it'll get auto populated through tool validation. Is this possible?
Just a disclaimer, I have never worked with tool validation so I'm new to it and any insight is greatly appreciated.