Join/match value in rows instead of separate column

[jw68937]

Happy Friday!

Looking for a solution for matching with grouping in rows instead of separate columns.

GL Mapping File -  GL Account numbers in G/L Account column (could be 8 digits or could be a combination of just letters or 8 digits plus letters)

Match File - Includes G/L Account numbers in Accounts column and underneath each group of account numbers there is a bold/blue consolidated G/L account  number that is 1-3 digits. There could be up to 3 of these numbers that relates to a group of account numbers. Where there is more than one I want to concatenate the numbers with a comma in between each. Example: GL account number 12284000 would pull in 64,17, 9

I'm looking to match the G/L numbers in file 1 against the numbers in file 2 and pull in the associated consolidated number that it rolls up to. If the 1-3 digit grouping was in a separate column that would be super easy but I'm a bit stumped with it going down in rows instead of columns, any recommended solutions? 

Thanks! 

[jw68937]

Added input files to make easier

[Luke_C · Accepted solution]

Hi @jw68937 

I don't think the files loaded, but I'd suggest trying out the multi-row formula tool to help: