Yes, grouping them is possible. Maybe you have worked on certain types of projects? (i.e. kitchen development projects, garage demolition projects, garden renovation projects, etc.) That would be a good way to group them logically. But frankly, since you are going to show this to your supervisor anyway, why not discuss it with him/her to see what you can come up with. After all... if your supervisor agrees that "this is the way we did it" then PMI will be happy to accept it.
Generally, PMI is seeking confirmation that you have indeed managed projects. They don't want to see and review every single, individual project and if they are small, and similar and grouping them makes sense then go that way.
I'm planning on submitting my PMP application some time in the next few days but want to run something by you prior to finalizing it:
All of my project management experience comes from a company who archives their project information after project closeout and sends it to an offsite location. I worked on around 40 projects over the last 5 years but about 90% of them have been archived. So it would be almost impossible for me to find all the project names and obtain exact hour estimates. Do you know if the PMI would allow me to group my projects together and name the Project Title: "40 Clinical Trial Management Software Systems" then list out my approximated hours?
....or would I need to submit 40 different Projects with names like "Project-1", "Project-2", etc.
I do intend to submit my hours estimates to my supervisors prior to sending in the application.