20 minute pauses? Ok, I've never heard of this. Occasionally, a game I'm playing will pause for 20 or so seconds, usually because someone's internet has decided to take a dump on our game, which has resulted in players being dropped however it's never even been close to a minute.
As it's happened to you and your friends, there is going to be a common element at play here since I haven't talked to anyone who has had a simillar issue.
Have you played with groups of people that are not your friends, as in against random people online, and if so can you recall if you experienced the issue?