VBA? Formula for pulling multiple dates for one part. Please help

Hi there-

I wasn't really sure if this fell under formulas or if this was best done using VBA.

To start, I'm still fairly new to VBA. So I'm hoping to get some help on this. If there is a better way to do this, please let me know.

Some background: There are certain part numbers with multiple projects on it. Currently it only pulls the most recent date but I would like it to pull mulitple dates if available.

I've attached a file to what I currently do. The formula in B18 is the following:
{=IFERROR(INDEX($A$2:$A$10,SMALL(IF(ISNUMBER(SEARCH(A18,$B$2:$B$10)),ROW($B$2:$B$10)-ROW($B$2)+1),ROWS(A18:A18))),"")}


It only pulls one date currently, but I would like it to pull all the dates whenever it sees the Dummy part number, separated by commas. The columns highlighted in Green is what I would like it to look like.

Please help!

Thanks in advance.

Bernice