If you own lantexco.com domain, then you shouldn't have to use fetchmail to pop from isp server. The isp should have a mx that points strait to your mail server. Otherwise, I use sendmail at home & comcast doesn't deliver without fetchmail. So...
Setup the mailboxes in webmin, and you have the passwords, then you just add:
poll pop3.lantexco.com with proto POP3
user 'whoever1' there with password 'whatever1' is 'po_box1' here
user 'whoever2' there with password 'whatever2' is 'po_box2' here
user 'whoever3' there with password 'whatever3' is 'po_box3' here
Be sure of what the pop server at the isp is named. Also, the users can't change the passwords on pop3. If they have an account at lantexco.com, then they gotta trust you. Otherwise, you probably own the domain, so you can set up the po_box & password, then plug it in to their client, like outlook.
I'm still trying to find the ans to run the fetchmail command everytime I reboot. You don't have to reboot often, so I just start it from the term window, logout & forget about it.
Good luck - this linux is fun.
Keith