title: How to make multiple phone calls at the same time
body: <p>I have an application, where I'll be having between 10-100 minimum phone numbers on which i want to periodically (let's say once a week) make a missed call (about 20-40 seconds of ringing and then hanging up, using all numbers "at the same time").<br>I haven't tried any code yet but i already looked up how to make calls, missed calls etc. so I hope I know my way around this stuff a little bit.<br>
  Now you see if I'd do it by using simplest way, I'd have about one hour of my phone making these missed calls one after each other.<br> Is there a way to make these calls somehow overlap each other (make them all at the same time)? Because I looked up that I can't make a phone call in background and since we are using activity to start a call, if I immediately start call after previous one, I suppose since it's an activity it's gonna pause.</p>