You may see if Call Park Tool feature is applicable. From DOC:
The Call Park Pool (CPP) feature is a specific configuration which utilizes the Internal
Group Hunting feature, SIP extensions without any physical terminal, and the call
Transfer and Call Pick-up features.
Using the CPP feature, a call can be parked ‘remotely’, at a dedicated CPP (hunt
group) member, which is a SIP extension. The parking is actually done by a transfer to
the hunt group member.
The parked call can be picked up (answered) from any telephone in the same system,
that can request the individual call pick-up service (or use MNS, if programmed).
A recall to the transferring party will be done if the transferring party is of generic extension
type, if the call is not picked within a few minutes. If the transferring party is not a
generic extension, it will not be recalled, but instead the call will be released.
If a recalled, previously transferring party, has several terminals (and thus uses
services like parallel ringing, personal number, or SCA), the recall will only ring on the
transferring terminal, except in the SCA case, where all terminals will be recalled.