i think you cant do this cause when you bump a Jotunn with another Jotun you get no points as there are at least two 5s in this line - the one you played and the one you bumped
also if there are already 7 pieces you cant bump a tile with the Jotunnj as you would have 8 tiles than
or did i misunderstand your problem?
In this example they have a line of 7 (where nothing is worth 5 or more) that they keep scoring by bumping Jotunn sideways. Jotunn doesn't score for the column because there is at least another Jotunn there, but can score 7 points for the line until the column is full.
You could also place a Dragon over Jotunn to score the 7 points and then the next person can place another Jotunn (unless the column is full) to bump the dragon and score 7 points.
This scenario is quite common when I play with my son.