Is it possible to call an xfinity smartwatch from a verizon phone line?

I have an inactivated Xfinity mobile line. I ALSO have a Verizon mobile phone line. 

I want to

1. buy a smartwatch device myself or through Xfinity, then

2. get a smartwatch line for it through Xfinity, then

3. call the smartwatch line from my Verizon line

Is this even possible?