WebPart Portal Personalization?

[ctadlock]

In .NET 2.0 web parts can be customized for all users
(PersonalizationScope.Shared) or for each specific user
(PersonalizationScope.User); is there any way to personalize web parts based
on a segment of users (like a portal)?

The product I'm working on is similar to DNN in many ways. I'm building an
application (single code base) that supports many different companies. I
would like to setup a system using web parts that allows the companies to
configure the web parts for their customers only. The enduser will never have
the ability to customize the web parts at all. The company is determined by
a request parameter (companyID). This would allow each company to setup
their website however they like. Note, the configuration of the website
doesn't require any login process from the actual user of the website, but is
determined by the companyID parameter.

I have seen some posts that talk about using the Membership.ApplicationName
to segment an application. I saw that the property is being changed in Beta
2 to be thread safe, however I'm not clear of the exact meaning of that in
this case. Does it mean that each request truly can set it's own application
name which won't effect other request? Are anonymous users segmented as well
when using the Membership.ApplicationName?

The hacky solution I have some up with so far is to forgo using the
membership system for its true purpose and give each company a user account
(a company is a user). When a page is requested, the application checks the
companyID parameter and tries to login to the membership system. This
technically works but has some drawbacks; you can't use the membership system
for actuall enduser login.

Does anyone have any ideas on how to resolve this?

Thanks
CT