With a little bit of modification you should be able to. I did have a play a while back and it would only show the first 3 portals on startup panel but if went to account management the extra portals would show up.
Although when you clicked on them you are not able to edit the details so technically can't login. With abit of modification and taking the same principle you have for the other options of editing the user and pass when selected then it would be possible I suppose.
It comes down to time and how much it is needed. You could sit there and modify the app for there to be another 4 released by time your done. They come out to fast now, any major modification isn't really worth it imo ?