Audience Etiquette - HELP!

At both the second and third performances, I had to admonish groups of students who were: 

constantly talking (at medium volume)

texting and playing video games on their phones

kissing / petting

eating candy 

In both cases, the students were sitting in groups in the back row(s) of the auditorium side.  I was able to get things in order, but of course, that was somewhat disruptive too.  On Saturday, it had a particularly adverse effect on the audience experience of Revisions.  

I discovered that these students were there to see friends in the show - friends who had invited them.  On Friday, the group left after Act One - (probably because they had flipped me off and did not want to deal with me at intermission - ha).  

I am well aware that we are in a time when audience etiquette is not something taught or even valued in our society.  This issue is not only a teen issue - it's everyone and everywhere.  It is a major point of discussion in theatre companies world-wide.  Entire conferences are being had on how to convince audience members to assist in creating a wonderful communal experience for everyone.   For the ritual of seeing a show is just that:  communal.  And unfortunately, in this era of "me, me, me, me, me" - exacerbated by smart phones and social media - it's becoming nearly impossible.  

If you are inviting people to the play who you know are not typical "theatre goers" - who aren't aware that when one talks in a theatre, actors and fellow audience members can hear them...who are used to IMAX level sound and so figure no one will be disturbed...who can't sit for more than two minutes without checking Instagram...who believe they should be able to come and go as they please (because "what about MY needs?) - please give them a friendly crash course on theatre etiquette.  

We want as many people as possible to attend - especially students.  So I'm not asking anyone to say to these folks:  stay away.  And I refuse to think that people - no matter their age or theatre going experience - cannot learn how to participate in the beauty of the live theatre experience.  It simply takes a bit of education.  So help out if you can...