Is there a way to have 2 validations rules for a group of cells.

I would like Row 12 I to Z to only be aloude X in so I would use the list validation. I would then like to use a custom validation of
=COUNTIF($I$12:$Z$12,I12)=1 so you can only put X in 1 cell in range I12 to Z12

Is there a way this con be done.

I would like it so you had a pull down menu with X as the only option.

Thanks