TPlannerItem height when Shape = psTool

For some TPlannerItems where I use Shape = psTool, I would like the height of the TPlannerItem to be only the height of the caption area. As per the image below, there's a lot of empty space below the "mycaption" header. I'd like to be able to eliminate that empty space. Is that possible?

image

If not directly possible, could you suggest another way of accomplishing some layout like the following, where there is an item with caption only, across a longer time period, with planner items below, something like the image below?

image

(edit: I should add that I can't use the group headers for this, because the grouping will be different for each individual planner row (Positions) )

The item height calculation is based on the position height and the possible number of conflicting items. I.e. position height divided by number of conflicts.
It is at this moment unfortunately not possible to override this built-in height calculation. To show such item with just a caption overlapping other items, perhaps you could use a separate position for this type of items above a regular position where the regular items are.