From /cgi-bin/koha/acqui/supplier.pl?booksellerid=X (and related pages), add links in the lefthand menu to /cgi-bin/koha/erm/agreements, /cgi-bin/koha/erm/licenses and /cgi/koha/erm/packages, limited to vendor X. I believe this would require modifying the ERM pages to accept a URL parameter (booksellerid) and apply that limiter to the results automatically. This would further integrate the ERM into Acquisitions in a simple but useful way.