Using Two HD Handsets on a Call

We have the Telo Air and four HD handsets. When a call comes in and it is answered on one of the handsets, is it possible for a second party to pickup one of the other three handset and participate in the call? Example: Daughter calls and both myself and spouse want to talk with her at the same time. Maybe it’s something semple. Any help appreciated.

Press the green key on the other handset.
Note that the left soft key label changes to Join.
Press the left soft key.

Thank you big time Murphy. :slight_smile: