Usually departments will simply use the "Pound 3" code to forward their phone to another in the office if their's is busy. But often they request a specialized Hunt Group to "roll" their numbers. Hunt Groups can't be inadvertently canceled like a "Star 3" would a regular Busy forward. However, if a phone in the group does set their Busy Forward, it will override the Hunt Group and follow the Forward Busy setting instead, disrupting the roll.
Hunt Groups are best suited for DTerm Multi-line phones because a button can be dedicated to the "Do Not Disturb" feature, that way the line appears busy and the system will roll to the next available number. Simply leaving your handset off-hook in an attempt to bypass the roll will cause the Telephone System to go into an alarm condition and lock your phone out, stopping the roll dead in its tracks.
There are three types of simple Hunt Groups, all are free to implement. Please contact Telephone Services if you need more information.
Pilot Hunt Group
There is a "main" number (the "Pilot"). Only calls to the "Pilot" number roll.
Circular Hunt Group
A call to any of the phones in this Hunt Group roll to the next in the "Circle".
Uniform Call Distribution (UCD)
This would have a "Pilot" number, then as calls come in the rest in the group would get them in a uniform fashion. So after the Pilot gets the first call, the second rolls to the second phone, third call to the third phone etc., until the number of phones in the group is exhausted and the next call rolls to the Pilot and the sequence starts over.
Automated Call Distribution (ACD) is often called "UCD on steroids". An ACD group allows advanced options and reports for a supervisor like call amounts and duration, who was logged in to answer them, etc. ACD is relatively expensive and requires DTerm phones.