Hi Fred,
I tried as you suggested and came up with the following:

=AND(INDIRECT("I"&ROW())="A"),INDIRECT("I"&ROW())= "T"),INDIRECT("I"&ROW
())="AC"),INDIRECT("I"&ROW())="AB"))

It gives me an error message that something is wrong with the
formula....have I missed something?
Thanks for your help!
Ken