Returning multiple matches and and displaying in a single cell with using UDF

Hello everyone, This is my first post so I hope I provide the appropriate information to help come up with a working solution.

First I will start with my requirements:
1. It has to work with SharePoint and the Excel viewer/editor.
2. It can't use UDF because of #1
3. It has to use multiple workbooks because one is replaced daily by an automated system. (I only need to read from this workbook)

Workbook 1 (This is where data entry and formulas reside)

ProductID (A1)	TrackingIDS (B1)
AH0001	12345, 67890
AH0002	123, 456, 789

WorkBook 2

TrackingIDs (A1)	ProductID (B1)
12345	AH0001
67890	AH0001
123	AH0002
456	AH0002
789	AH0002

Worksheet 1 column B needs to be populated with the values from Worksheet 2 where Worksheet 1 Column A equals Worksheet 2 Column B.

Any number of rows will need to be returned by the formula. It could be 0 or it could be 20.

I have made this work with UDF but I need to do it with a formula if possible due to the SharePoint and Excel Web component requirements.

Thanks for all your help in advance.

There are going to be limits. I set a maximum of 5 Tracking ID's per product in this ARRAYED Formula in B2

=TRIM(IFERROR(INDEX(Sheet1!$A$2:$A$6, SMALL(IF(Sheet1!$B$2:$B$6=A2, ROW($A$2:$A$6)-ROW($A$2)+1),1)),"")&" "&IFERROR(INDEX(Sheet1!$A$2:$A$6, SMALL(IF(Sheet1!$B$2:$B$6=A2, ROW($A$2:$A$6)-ROW($A$2)+1),2)),"")&" "&IFERROR(INDEX(Sheet1!$A$2:$A$6, SMALL(IF(Sheet1!$B$2:$B$6=A2, ROW($A$2:$A$6)-ROW($A$2)+1),3)),"")&" "& IFERROR(INDEX(Sheet1!$A$2:$A$6, SMALL(IF(Sheet1!$B$2:$B$6=A2, ROW($A$2:$A$6)-ROW($A$2)+1),4)),"")&" "&IFERROR(INDEX(Sheet1!$A$2:$A$6, SMALL(IF(Sheet1!$B$2:$B$6=A2, ROW($A$2:$A$6)-ROW($A$2)+1),5)),""))

I have a simple space separator because if you use commas, you end up with extra commas at the end of the string.
...confirmed by pressing CTRL+SHIFT+ENTER to activate the array, not just ENTER. You will know the array is active when you see curly braces { } appear around your formula. If you do not CTRL+SHIFT+ENTER you will get an error or a clearly incorrect answer. Press F2 on that cell and try again.

Here is an example of it for 6 duplicates and rows 2 to 600. This formula takes a lot of memory and the larger the range, the longer it will take to calculate (depending on your computer). It may not have been returning a blank field, just not done calculating. You may have to go get a cup of coffee or tea. If your range is too large, it becomes impractical so keep it as small as possible. The range of "infinite" that you suggested is definitely too large.

=TRIM(IFERROR(INDEX(Sheet1!$A$2:$A$600, SMALL(IF(Sheet1!$B$2:$B$600=A2, ROW($A$2:$A$600)-ROW($A$2)+1),1)),"")&" "&IFERROR(INDEX(Sheet1!$A$2:$A$600, SMALL(IF(Sheet1!$B$2:$B$600=A2, ROW($A$2:$A$600)-ROW($A$2)+1),2)),"")&" "&IFERROR(INDEX(Sheet1!$A$2:$A$600, SMALL(IF(Sheet1!$B$2:$B$600=A2, ROW($A$2:$A$600)-ROW($A$2)+1),3)),"")&" "& IFERROR(INDEX(Sheet1!$A$2:$A$600, SMALL(IF(Sheet1!$B$2:$B$600=A2, ROW($A$2:$A$600)-ROW($A$2)+1),4)),"")&" "&IFERROR(INDEX(Sheet1!$A$2:$A$600, SMALL(IF(Sheet1!$B$2:$B$600=A2, ROW($A$2:$A$600)-ROW($A$2)+1),5)),"") & “ “ & IFERROR(INDEX(Sheet1!$A$2:$A$600, SMALL(IF(Sheet1!$B$2:$B$600=A2, ROW($A$2:$A$600)-ROW($A$2)+1),1)),""))