Excel Conditional Format

I am trying to implement some sort of conditional format or If/Then formula that will return a color (either RED or GREEN) to a cell if a condition is met in another grouping of cells. For example, I want to tell Excel that if, in a given grouping of cells on one page there is a value (X), color this cell (on a different page) RED. If there is no value (X), then color this cell (again, on a different page) GREEN.

Can anyone advise the best way to go about this?