I have 3 sites (or sometimes more) that I manage using Google Analytics, i.e. I have 3 "properties":

How can I create my own dashboard that displays graphs of page views for each of 3 sites on one page?
Something like that:

When I tried to use the setup function , all I was able to do was a custom control panel, but for a specific property :

How to create a custom panel that can display data from multiple properties / multiple websites? (to get an overall picture of traffic for several sites at a time)