I have 3 cells set up with data validation. The data validation for each cell
is a list with only one option, to select and X.

Is it possible to keep the data validation in these cells, which will allow
the user to select and X, but combine it with a formula based on the
following.

If cell I38 has an X, then the X can not be selected for cells L38 or N38.
If cell L38 has an X, then the X can not be selected in cells I38 or N38.
And last, if cell N38 has an X, then the X can not be select in cells I38 or
L38.

If this is possible, please explain how. If not, is there another
alternative?

TIA
Jan