Prevent Duplicate entries in multiple column from VBA Userform

Would it be possible to have another column, maybe hidden, with a formula that combined the B and C values, and then compare your entries with that? So your formula in G2 would be

Formula:

=B2&C2

and your code would be

If Not (WorksheetFunction.CountIf(ws.Range("G:G"), ComboBox3.value & ComboBox6.Value) > 0 Then