These are radio walkie-talkies. As long as only one handset transmits at any given time, there is no limit to the number of devices listening on the same channel. With 12 devices it's only a matter of following proper radio etiquette to make sure there is no uncontrolled chatter. Motorola TLKR radios also feature a group calling mode. To my knowledge up to 16 devices can join such a group as the available ID numbers are between 1 and 16.

These are radio walkie-talkies. As long as only one handset transmits at any given time, there is no number to the number of listening devices on the same channel. With 12 devices it's only a matter of following proper radio etiquette to make sure there is no uncontrolled crosstalk. Motorola TLKR radios also feature the group calling mode. To my knowledge up to 16 devices can join such a group as the available ID numbers go from 1 to 16.