Cardo users

[8IKERDAVE]

I have the Cardo packtalk slim fitted to my lid and my mate has the other one. I've started taking my lad on the back and would like him to have an intercom but as it will only ever be used on the same bike I can't help thinking there must be a cheaper way of doing this other than purchasing another Cardo unit.

Am I right in thinking any other Bluetooth intercom will do the job and if so are there any that people recommend?