A long-shot but here it goes...what is this book?

Question

The book I am trying to identify is one written for young adults and here's the synopsis.

A boy and his family join a new church which turns into a cult. Then all the members of the congregation leave all their houses and possessions to move to the top of a mountain to prepare for the oncoming armageddon. But when the time of reckoning comes, a apocalypse takes place, but within the church instead of the whole Earth. This book is written by two authors. Any help would be fabulous and VERY well appreciated.

Answer 1

Is it the Left Behind series for young adults? That has two authors. Tim Lehay and Jerry Jenkins.

I have never read them though, so I might not know what I am talking about.  

Answer 2

I think I know the book you're talking about. I believe it is called "Armageddon Summer" by Jane Yolen and Bruce Coville, both amazing authors of books for young adults. If the book you're thinking of is split between the narration of a boy names Jud and a girl named Marina, then this is it.

Enjoy!