array formula to provide all values associated with a given value
 

From an Access Query. I've got a list with the unique ID's for reports, and
the next field indicates what Language they were written in.

This was from a Many - Many relationship in Excel, and many of the reports
were written in many different languages.

ReportID CountryID

1000020 Td

1000020 Tz

1000020 Ug

1000020 Zm

1000020 Zw

1000035 Ao

1000035 Mz

I've got over 10,000 records like this and would like an array formula that
for each Report ID (and i've got a separate list of those of course)
provides a listing (preferably tab or semicolon delimited) of every single
country that that report covers.

Any suggestions?

Thanks - Toby