Siemens 300Series User Manual page 135

For a linear-pattern pilot hunt group, if all the members of the group
are busy the call will then be placed in a system queue until one of the
members becomes available. If no queue has been set up at the
communications server, or if all queue positions are occupied, the
caller will receive a busy tone. If a call advances to the final member
in the group, that phone will ring until it is answered.
Note: On Version 6.3 and higher, the final member in a linear-
pattern pilot hunt group can forward calls to any other call-
forwarding destination.
For a linear-pattern station hunt group, after the call has advanced to
the last member and the last member is busy, the caller will receive a
busy tone. However, if a call advances to the last member and the last
member is not busy, that phone will ring until it is answered.
Managerial Features 7-7