If loop on a DataFrame (python)

I have two dataframes df1 and df2. The two dataframes contain a 'dispatch' column containing random letters between A and Z. I would like an if loop that does this:

*

if any 'A' on one dataframe AND ((a different 'A' or 'B' or 'C')on the same or the other dataframe) return True else return False.

*

please can someone help me ?