Hi everyone.
I've got 2 spreadsheets. The first one, named "DATA" consists of 4 columns:
column A: product ID (thousands of records; unique numbers)
column B: name of group where each product belongs to (there are
hundreds of product groups; each group consists of several products)
column C: product description
column D: product price

It's more less like this:

product ID |name of group |product desc.| price
| | |
Product_1 | Group_1 | abc |x_EURO
Product_2 | Group_1 | def |x_EURO
Product_3 | Group_1 | fgh |x_EURO
Product_4 | Group_1 | ijkl |x_EURO
Product_5 | Group_2 | mn |x_EURO
Product_6 | Group_2 | op |x_EURO
Product_7 | Group_3 | xyz |x_EURO
Product_8 | Group_3 | fg |x_EURO
Product_9 | Group_3 | por |x_EURO
..
..
..


There is also a second spreadsheet named "GROUPS". There is a combo box
with a list of all groups. Now, after selecting a name of group, I would
like to receive all of its members (product ID will be sufficient).
Unfortunately I don't know what kind of formula or formulas should be
used to do so. I don't want to use a filtration from the main menu. Any
clues?

Regards,

gordom