I would like to customize the customer search page (initial customer admin page)

I have a custom property set for each customer that admins control.
I check this and display a message on the admin header links indicating that they have users to administer/check.
When they click this link I retrieve the customer objects but i am unsure how to pass these on in the CustomerController.

I am modifying the ActionResult List(),
I Check if the query string contains my search character if so:
Get a list of the customers with the custom attribute.
Not sure how to pass this on to the view ( the current model seems to all be about roles and not id's?)

Any help appreciated.