Drop-down menus in tables and removing used items from that menu

[ctroxtell]

Hey guys, I'm hoping someone can help get me on the right track. I'm working on an Excel sheet that has 100+ addresses on it with employees on the sheet. I'm trying to make it so the drop-down menu will only allow the list item to be selected one time. The sheet has 10 tables, 1 for each staff member with a column in a table labeled Address, then I've created a table that holds my entire list of addresses. How can I hide the addresses that have already been selected from the drop down menu? Currently using Excel 365, I was experimenting and had got it partially working with COUNTIF but it wouldn't translate when I selected the entire address column

 

[Peter_SSs]

Thanks for the detail.
You can turn that warning off in File -> Options -> Formulas -> Error checking rules -> Uncheck 'Data entered in a table is invalid' -> OK

 

[Peter_SSs]

@ctroxtell
Post #11 is clearly not a solution to the thread question so I have moved the 'Mark as solution' from that one to post #7. The mark should be used to indicate the actual solution post to help future readers quickly locate the solution if they have a similar question.