Using Echo as an intercom

[abc4515@msn.com]

I have an Amazon Echo and 2 Echo Dots.  I want to use the devices as an in-home intercom.  I know I can say something like "Alexa ... announce dinner is ready" directed to my Echo and that announcement will be sent to the 2 Echo Dots. 
Can I direct a message to a specific Dot?  Maybe something like "Alexa ask Joe to come upstairs".

Thanks,
Alan