IMessage showing up on another device when not supposed to

Question

Ok, recently I have came across this VERY frustrating experience with iMessage. Here is a brief background on how I set up my account:
In my family, we have several iPhones (4 & 4s) and iPad (1 & 2). Since we all want to share the music and apps under the same Apple ID but not our imessages/facetime, I decided to create an unique email address as the sent & receive address for each individual device. So for example, I would have let's say [email protected] as the email address on my mom's iPhone, so that any imessages or facetime sent to that email will only show up on my mom's iPhone whereas the [email protected] would be on my dad's iPad etc. We have been using our own email addresses all this time without any problem until we upgraded to iOS 6.
Here are the problems we have been encountering recently:
1. At times, our iMessage would log out by itself and make us re-enter the password for the Apple ID.
2. With the new iOS6, I noticed that we would actually see a list of all the email addresses that are associated with my Apple ID show up under Setting > iMessage or Facetime. At first, they all had check marks in front of them and eventually I figured out that I would actually receive all the imessages that are sent to the email addresses I have a check mark for. For example, if in my iPod setting > facetime, I see that [email protected] and [email protected] are both checked, that means whoever sends an imessage to my mom's iPhone or my dad's iPad, I would also be able to see it. So what I did for each single device was to uncheck all the other email addresses in that list and only checked the one that the device has always been using previously.
At first, everything worked fine, we all got our own imessages without getting others. But after a while things started to get out of control. One night, I was using my iPod (which uses the email address [email protected]) to send an imessage to my friend's iPhone (which uses her own phone #) and next day, my mom told me that she saw my imessage on her phone too! And it appeared as if she was the one sending it out instead of me! Similar problem happend a few days later, where my dad's imessage with his colleague showed up on my iPod.
But I re-checked all the devices and made sure that only ONE email address was used for each single device and they are all different from each other. So has anyone encountered this problem? Any way to solve it? It's kind of scary because your private messages with friends or girl/boyfriend would just randomly show up on your parents' devices once in a while @@
I would really appreciate it if someone can lend me a helping hand! Also, this is my first time posting on Apple Forum, so I sincerely apologize if I happen to put this at the wrong section. Thank you!

Answer 1

all ios devices which are signed in wiht the same appleID get all imessages same deal with facetime
make an appleID for each device