I have a large spreadsheet with 11 columns of data. Column B is a reference
number, column F is an amount attached to the reference number. There may be
multiple amount entries attached to a reference number but they are all
individual data lines.

What I would like to do is a formula or macro that checks column B and if
there are multiple entries for the same reference number, adds up the amounts
and if the 2 or more of the entries equals 0 to put an indicator in the next
empty column L.

Has amyone any idea how to do this as I am currently doing this manually and
with a 50,000 odd lines of data, it takes forever.

Any assistance gratefully accepted.

Thanks

Shazzmo