Grouping Milestones by Project instead of Parent Folder?

Hello!

I have encountered a milestone reporting challenge with our project template and wanted to know what the community has experienced and if you guys have some ideas for resolution.

First off, we follow a typical Phase/Stage Gate process for new product development.  In order to group our tasks by phase, I've created a sub-folder under the project folder representing each phase (see below).

We have a number of specific milestones spread across multiple phases the we need to track/report on throughout the year.  Because each product's development cycle can fluctuate significantly (and Wrike milestones don't move after setting the project start date), I've created a custom field as a checkbox labeled "Milestone" which allows me to filter tasks in my reports by this custom field.

In my report, I don't need to see which phase (parent folder) the milestone is in, I just want to group the list of milestones by the project.  Because of the nature of our business, we typically have about 15-20 new product schedules rolling throughout the year.  Reports need to be "noise-free" to help meetings move faster, and phase folders become noise in those meetings.  The options I have come across so far are (1) eliminate custom grouping from the report which gives a list as shown below (not ideal or noise-free).

Or (2) create another custom checkbox field called "Top Level Project" and group by this custom field as shown below

The later view is what I really need, but unfortunately it does not show the project name, only the word "No".  I presume this is because it is a task-based report rather than project based.

My next thought is to turn my phase sub-folders into parent tasks containing the tasks I've already defined as sub-tasks.

What thoughts and ideas do you guys have that could help my report grouping?  Thanks in advance!