You can do this in three different ways:
a) Add a second Pages widget, then exclude the PPM pages from showing in the first widget and exclude the PP pages from showing in the second widget.
b) Create two custom menus (one that lists the PP pages and one that lists the PPM pages), then remove the Pages widget and add two Custom Menu widgets instead (one for each menu).
c) Create links to all your pages in Links > Add New, filing them under a PP or PPM link category, then remove the Pages widget and add two Links widgets instead (one for each link category).
Method b is easier. For details see this post of mine:
You understand that no matter what method you use, you'll have to update things manually each time you create a new page (while a Pages widget that displays all your pages updates automatically).
Also, in my opinion your sidebar list is already too long. So another possibility would be to remove all the page links from the sidebar and create an Index page instead.