Cisco recently released Jabber for Windows 10.5 which introduces support for notification of calls to hunt groups & group pickup capability. However these features aren't enabled by default & the Call Pickup/Hunt Group sections in the Jabber Jabber deployment guide don't actually tell you this, nor does the release notes or the advanced functionality guide. To enable these features you need to add some parameters to jabber-config.xml, the deployment guide does list these parameters in the Client Configuration > Configure Users > Policies Parameters > On-Premises Policies section.
Below is an example jabber-config.xml that enable hunt group notification, pickup & other group pickup:
<?xml version="1.0" encoding="utf-8"?>
As per usual, this needs to be uploaded to all your TFTP servers & the TFTP service restarted.