Scale group via child object

Hello CorelDraw people

I searched around this group and couldn't find this topic, so I hope this is not a repost or in the wrong place.

I work with signage and do lots of precise scaling. Sometimes I need to have a specific part of a graphic at a certain size. For instance, the letter "P" must be 500mm high.
Obviously the rest of the sign, grouped and/or combined with the "P", need to scale along proportionately.

The way I'm currently doing this is quite clumsy - I make a 500mm box and scale the entire group through trial and error untill the matches the 500mm box's height, using guidelines. Or, I can ungroup and break apart everything, note the percentage needed to match the P to the box, then go back and scale up the entire sign by that percentage to get the required result.

I'm sure there is a better way of doing this.

It would be incredible if Corel allowed you to scale a group of items by adding handles to one of the child elements, and then upon scaling said element, the entire group scales accordingly.

  •   has shared a very clever process that uses PowerClip (temporarily) to carry out "precision scaling". See this thread: Sizing??.

    I wrote a macro that works very well for precision resizing, but I wrote it in X7. I don't know if it can be used in anything older than that.