Backing UP the Outlook PST Files

[kn6p]

I am using Office/Outlook 2010 on a PC running System 7 and I have a question concerning how to backup the PST files in Outlook when using four accounts/email addresses.
When I called Microsoft Tech Support, I got conflicting information which leads me to believe the MS Tech Reps are not familiar with backing up the PST files on 2010 Outlook.
On my computer I have four accounts/email addresses and my question is, can I backup the PST data with one backup or do I need to do a backup on each account/email address?
When I do a backup the way I think it should be done, a file is generated in a folder I specify and the backup file is named "backup.pst". This file is not account/email address specific therefore I think it probably backs up all the accounts.
Does anyone have any works of wisdom that would be beneficial to my understanding this problem?