Group.by inside a Table.NestedJoin query

Dear all,

I have a question regarding the Table join options available in Power query.

Indeed, I have 2 tables and I need to join them via Table.NestedJoin query, but as I can’t group the columns of the Table 2 via the key column before the joining because I’m using the columns of this table in different visuals , I would like to know if there is any option to import the columns from Table 2 to Table 1 and use a query to display the grouped columns from Table 2 without duplicating Table 2 just for this grouping step because it’s a heavy table.   

Thanks a lot for your help in advance!

Regards,