Hello Matt,
If the accounts are set up as MAPI the easiest way would be to add the user as a share
This will connect all shared devices from that user to this account in one step. If this is a domain resource and not from a user you will want to use the "Internet Calendar" option. To get the webcal address you can select the calendar from the web interface and enable the sharing option.
From here you will want to add to outlook.
Please let me know if you have anymore questions. Thank you
Tony Scholz
System/Network Administrator
SmarterTools Inc.
www.smartertools.com