Find In Table, Then Concatenate Results

My data is pulled in as a table from QuickBooks, so its many rows consisting of many column entries per row. The columns are laid out like:

DUEDATE, VENDOR, ISPAID, PONUMBER, AMOUNT

I currently have a SUMIFS formula that works well for searching the table and finding PO's that are not paid, for a specific vendor, on a day today or before, and it ads the amounts together and returns the sum opf the amounts for me.

Now, what I would also like to do is to have it return the PO numbers as a concatenated text string all into one cell. So, it shoudl find all the rows where the due date is today or before, the PO has not been paid, and the vendor is a specific vendor, and then concatenate all of the PO numbers into one cell of my choosing.

This sounds just like the SUMIFS function, however, the SUMIFS function adds the values and places the sum in the cell of my choosing. For this, I would like the values found (which are text values) to be concatenated into one cell.