Hi Ryoma,
This is possible with a simple domain model that has set the Navigability to Both entities like below.
And on the page a structure with a tab container for example. A listview left with datasource from database the members. Right a dataview listening to the left widget with inside a listview of the associated projects.
And on the other tab ofcourse the reverse with project as the datasource and the member association in the listview on the right.
Hopefully I explained it well enough for you with the provided screenshots.