I have an interesting request.

For this example, lets assume we have 5 columns. First column contains data
values. The 4 additional columns are blank. I want to be able to manually
distribute the values in the first column using data validation list. Now,
here's where it gets tricky. Once a unique data value in the first column is
selected, and is moved into one of the following 4 columns, I want that
selected data value in column 1 to appear blank. However, if I was to remove
the data from columns 2-5, I'd like for it to reappear in column 1.

Is there a way to do that?