concatenate cells and delete rows with a twist

I have a spreadsheet with three columns (check #, invoice #, vendor #). If a check pays multiple invoices, there is a separate row for each instance of invoice #. (ie if a check pays 10 invoices, there are 10 rows all with the same value for check # and vendor #, but different invoice #s). I need to concatenate the multiple rows to just one row per check #, with all the invoice #s in separate columns on the same row and delete the duplicate check # rows. However, I can only use 10 columns, so if there are more than 8 invoices matching the same check #, the 10th column will need to contain invoices 9-n concatenated and separated by a space.

I have over 5000 rows in the spreadsheet.

This is what I have come up with so far for the concatenation part:

Please Login or Register  to view this content.

Usage is =ConCat (A1:A6, “ “) entered in a cell.