This is more or less what I thought.
But several departments editing the same spreadsheet at the same time doesn't work well in Excel. So my thoughts were to give each department it's own spreadsheet (filling 1 column), mail it to the central secretary, who then copy/pastes that one column in the right column in her own spreadsheet, to fill the whole 'matrix'.
That's where a macro would be useful. And, having a macro that copies the column to that central spreadsheet, there isn't even a need to mail that file, because each department can just press the 'Order' button in its own spreadsheet.
But as long as macro programming is out of the question they will keep mailing, I'm afraid.