I also had this prob. and was lurking in this thread while trying to figure it out and i think i found a solution - so i made an account.
You probably had problems because filtering for something will not show their children if they dont have the same tags right?
You can group for your wanted view and then hide all other tags.
Lets say you group for Medicine then the Children and their children like Sonography, ultrasound etc. will be still shown
In this View everything tagged with medicine and their infinite children will be shown this is very dynamic.
If you want only one to be shown and be dynamic if you add a new entry to the database i recommend making a new property for it and hiding it in all other views that is unique to it
You might think if i only want one thing then i just group by name and ID because filtering does also filter the children and grouping doesn't - Good thought but if you have a huge database you'd need to manually hide all other views you could group which if you have thousands of notes is very hard because you only can hide like 10-20 names or ID's that have now become a group on their own every time so either you sit their and click hide all for hours or you make a new group until their may be a better way to do it.
Screenshot of grouping by tag - "this"
Screenshot of grouping by status - "active"