I have asked my guests to enter mobile number and name in a form.

Now in my base, the mobile number will be a unique value that will be used for linking to another table.

But I can’t link a column with a formula (concatenate) & if I convert phone-number or a text column into the linked column - then a new guest will not be able to enter data in the form but will have the option to choose someone else’s number only. Any suggestions?