Sharepoint Lists many-to-many relation

Thank you Beau Cameron for your note. Finally I was able to achieve partial success with Power automate flow.

1) Products table with Groups field as a multiple lines of text 

2) ProductGroups table with Products lookup field, multiple values allowed

3) Flow triggered with each ProductGroup change which will:

1. Clear Groups field for all Product records
2. For each record in ProductGroup and for each record in its Products lookup field find matching record in Prouducts table and update its Groups text field (concatenate with previous value) with link to particular ProductGroup. This is just an example of updated field value:

concat(item()?['Groups'], '<a href=', items('Apply_to_each')?['{Link}'], '>',items('Apply_to_each')?['Title'],'</a></br>')​

Result looks like this:

The only disadvantage of my original intention is that Groups field inside Products table is a http link without option to link Product with ProductGroup. Table (okay, better say list) linking must be always made from ProductGroups table!