VB.NET Role-Based Access

Hi all,

Am trying to implement some security on my program. This program will
be run on a number of machines across the globe. I have created a
number of user groups which contain the access priveleges of the
windows users but as they are not builtin groups I cannot do as below!

<PrincipalPermissionAttribute(SecurityAction.Demand, _
Role := "BUILTIN\Backup Operators")> _

What I need to know is how can I change the Role attribute to look at
my user-defined groups instead of the builtin groups? And as i dont
know the Domains that users are working in, How do I add that to the
attribute???? Really need something like below but it doesnt work:

<PrincipalPermissionAttribute(SecurityAction.Demand, _
Role := "AllowedCreation")> _

Thank you