T41S pickup call with Swyxit

[qaztan]

Good morning.
In my company we have recently installed about 20 T41S phones. I need the function "pick up call" to take the call of another user when he's not as his desk. I checked the manual, but i don't understand how to configure groups, if i need an additiona software or what. The adimistrator of the service "Swyxit") already configured the groups to work with the VoIP software on our computers, but we also need this function on the VoIP phones. Do you have any solution?
Thanks.