Conditional formatting based on another cells value

Hi All,

Thank you for any help.

I am trying to set up a conditional format for a column of cells ("G3:G400")

These are the conditions for the cells.
If the cell is empty then no colour in the cell
If this cell's value does not equal the other cell's value and is not in the specified range then turn the cell red
If this cell's value does equal the other cell's value but is not in the specified range turn the cell red
If this cell's value does equal the other cell value and is in the correct specified range turn the cell green


Specified Range is cells ("M3:N3") of each row all the way down to row 400

I am stumped. I think I should be using case statements, but I can't figure out the syntax for the case. I am thinking offsets, but again I'm stumped.

Thanks