How to auto-fill text based on text in another cell TWO WAYS

Hello,

I need to know how to auto-fill text based on data in another cell so that the auto-fill will go either way.

Currently, I am using a list of data from a second sheet to select a company practice. In the adjacent cell, it auto-fills with the code number for that practice. I would like to be able to also enter the code number and have the company practice cell auto-fill based on that information. How can I set up a list like this? Any ideas?

I tried copying the vlookup formula into the cell with the company practice, but the error that occurred said there are one or more circular references. It makes sense that I cannot accomplish the two-way auto-fill like that, but I am wondering if there is another way.

The purpose of this would be to have the information fill based on whichever answer the person using the spreadsheet knows. If they know the code number and select it, the practice name will fill. If they only know the practice name and select it, the code number will auto-fill, and the table will have both pieces of information showing.

Thanks,
Sara