Filter Picklist by shared status

Filter Picklist by shared status

Does anyone know of a way to filter a name picklist to show only those people you have shared access to your application?  To clarify, I have a form, emp_list, which contains all of the employees for our company with their correponding email address, which is their zoho.loginuserid.  I would like to filter the employye list in the lookup field so that only users that are active in the application show up.

Thanks