I am building a new instance of Service Desk Plus.  I have imported requesters from Active Directory but when you login there are 3 domains available e.g.

THECONSORTIUM

theconsortium.com

WORKGROUP

Local Authentication (SD authentication)

I'm guessing the SD software has pulled these from my AD.  I only need THECONSORTIUM as this is the domain everyone logs in against.  How can I remove the other 2 selections from the drop down?

Many thanks,
Lee