Analyze: How to get total of sub projects per custom field value

Hi everyone!

We've set up an Analyze board to view our company processes with consolidated values. We have process levels 1 to 4 and each process is created as a project or subproject, depending on it's level. Projects on level 1 are our level 1 processes, level 2 - 4 are respective subprojects.

We'd like to analyze how many subprojects of each level, a level 1 project has. For Example: Level 1 project has 12 projects on level 2, 15 projects on level 3 etc... We maintain a custom field for the different levels, so we are able to filter and break by it - but currently aren't able to consolidate the numbers for our top level (level 1) projects. We are not getting what kind of formula is needed in order to count and categorize the subprojects by level. 

We've added a draft from excel how it shout look like (approximately), see screenshot at the bottom. Do you have an idea what filter or formula we need to add in a widget to get the consolidated numbers of sub projects per top level project?

At the moment, we could manage that the first row shows all projects, but without their respective hierachy - instead, every (sub-)project is shown on the same level as a single project (see screenshot below):

I'll be happy to dive deeper in explanation if our case is unclear to you. Thank you to everyone who has an idea and could share it with us!

Here's our vision for the widget: