Different Query Results For Different Users?

I have an SQL2K5 database where a group of users share a custom database role and access the database via trusted connections (Windows authentication).

I have a stored procedure which reports all of the users in this database role using an SQL statment something like this:

select name
from sysusers
inner
join sysmembers on
sysmembers.memberuid=sysusers.uid
and sysmembers.groupuid=7

As the programmer, and the dbo, when I log in to execute this query, I get the list of a dozen, or so, users.

When one of the users executes the same query, they only see a return of their own username.

I'd like to have the users be able to execute this query and get the full list of users. Can someone tell me how to accomplish this?

I assume that this is some security, or permissions, thing involving system tables, or Windows authentication security.

Thank you.

BTW--the users never actually directly execute the stored procedure I mentioned; They are using a VB client application that affects the execution.