I'm sorry, I think we're having trouble understanding each other. Let me try to spell it out a little differently:
You cannot create duplicate Web Security Accounts in Astaro.
You cannot prevent the same Astaro user account from logging on more than once at the same time.
If you want to give out a single ID and password to all your users, you CAN do that (though it's not recommended because you cannot tell who was actually logged on).
If you want to prevent someone from logging in from more than one PC at a time (or giving his password to his buddy so they can both log in at once), then you CANNOT do that.
I'm sorry, I think we're having trouble understanding each other. Let me try to spell it out a little differently:
You cannot create duplicate Web Security Accounts in Astaro.
You cannot prevent the same Astaro user account from logging on more than once at the same time.
If you want to give out a single ID and password to all your users, you CAN do that (though it's not recommended because you cannot tell who was actually logged on).
If you want to prevent someone from logging in from more than one PC at a time (or giving his password to his buddy so they can both log in at once), then you CANNOT do that.