I made a function to search a sheet to match a cell on another sheet.

=IF(COUNTIF(M16M4M203!$O3:$O24,B3)0,"X","")

This works great, but I need it to only search certain cells on the sheet. I
tried to just select those cells and control-click another group but Excel
tells me "You've entered too many arguements for this function"

Do I need to make a function for each range of cells to search? If so, how
do I put more than one function in a single cell.

Thank you