How to strikethrough a text if the text is the same in another cell using conditional formatting?

Question

I am making a table assignment for the guests for my brother's wedding. I want to know if it's possible to conditionally format to strikethrough a cell that has the same text as another cell. In this case if I already assigned a name to a certain table (a specific cell), I want it to automatically have a strikethrough.

GUEST NAMES	TABLE ASSIGNMENTS	TABLE ASSIGNMENTS
John	TABLE 1	TABLE 2
Stacey	Jacob	Stacey
Jacob	Hannah	John
Hannah

Answer 1

Your conditional formating rule would be:

Range:          C3:Z22
Custom Formula:  =COUNTIF(TOCOL($B$3:B$22,1),C3)

This assumes you have a maximum of 20 guests per table. You can change the max by adjusting 22 in both the range and the formula.

I added a sample Sheet with a more advanced approach that you can play with if interested. Anyone with the link can edit it so you should probably make a copy to your own Drive while it is working

1. The guest list is managed on one tab
2. The seating arrangements on the other.