Yes. From version 7.4.2 you can specify for a leg that it should be marked, and this will be reflected automatically in the control descriptions.
Double click on the leg line, and tick the box "Follow streamers on this leg".
If, instead, you wish to mark only part of the leg, you need to insert an "end of marked route" object at the point on the map where you want the marked route to end. (There is a tool in the toolbar on the right that lets you create such "end of marked route" object)
Then insert this object in the appropriate leg on the course.