I think you will have to create the separate 7 graph widgets per port as you don’t want an accumulative graph.
I quite like the idea of this feature request to make things easier "Send to Dashboard" link so help to upvote it 
You can also think about doing something like this Aggregating bandwith graphs from interfaces on seperate devices? - #4 by Chas where if the port descriptions start with they same keyword, it will automagically add them all to the same page. (not on the dashboard though). You can also use the port ID instead of changing descriptions to create the page Single graph, Multiple interfaces - #3 by murrant