I am currently trying to look at C18:C20 and compare that to C22:C24.
And if they are the same then do C18+C22, C19+C23 and C20+C24. But it
keeps erroring saying mismatch. I've tried to reduce the range(to only
2 rows as shown in the code below) but the only time it will work is
if I just do one cell at a time but I need the macro to look at the
group.

Sub test()
Dim rang1 As Range
Dim rang2 As Range

Set rang1 = Range(Cells(18, 3), Cells(19, 3))
Set rang2 = Range(Cells(22, 3), Cells(23, 3))
If rang1 = rang2 Then Cells(18, 7) = (Cells(18, 7) + Cells(22, 7))
If rang1 = rang2 Then Cells(19, 7) = (Cells(19, 7) + Cells(23, 7))
If rang1 = rang2 Then Cells(20, 7) = Cells(20, 7) + Cells(24, 7)
End
End Sub