Multiple projects and videos on one timeline

I have a number of projects and short videos that I want to put together on one timeline. It is a number of short items that I would like to put together as a concert (with some transition between the items). I will not want to edit the items once they are put together.

Is this possible and, if so, is it easy?

You can open a project (.mlt) as a clip by using the Menu item:

File -> open MLT XML as clip

You can do this for multiple projects.