2 homes, seperate accounts, multiple echos...how to specify which to call/dropin

[jim928]

I have 5 devices in my homes, all on my account and named for the rooms they are in.  My son recently put 4 echo dots in his home registered to his account and named for his rooms. 

If I want to drop in to, say, his "office", how do I ask Alexa to do that? Or I want to use my echo to 'call' one of his, how do I specify which device to call?  Right now I do a "dropin on Bob" (the name in my phone directory) and, for some reason, it drops in to his office....I'd like to be able to specify which of his echo dots to dropin or call.  Any help...couldn't find anything with an hour or so of googling.

Similar but different issue.
I setup an echo for my Mom, who lives in a different state.  It's registered to my account (she's 90 and doesnt have a smart phone but DOES love telling Alexa to "turn on the coffee"

so this is a sixth device on my account.  If my son wants to call my Mom's echo, how does he tell Alexa to do it? Is it something like "Alexa, call Dad Mom"?  Where" Dad" is how my contact info appears in his phone and "Mom" is the name of my mother's echo?

I'd assume the issue of communication between two households ea with multiple echos and each house on its account is a relatively common situation, or will be.
Appreciate any help.

[kenf]

I don't have your setup, but nobody who does has replied yet.

Here's my assumptions of best practice:
each house has its own Echoes tied to that homeowner's account.
each echo is named after the room it is in in its own house (ex, kitchen rather than Mom's Kitchen)

Within your house, if you were in the kitchen, and wanted to call the wife in the Office, you'd say:
"alexa, call the office"
Then the Office would ring and presumably your wife would answer.

To call your mom, assuming she is entered in your contact list as "Mom" you would say:
"Alexa, call Mom"

Since Mom isn't a room-named Echo in your house, it should scan your contacts she's in there AND her email address is tied to an Echo and her Echo should start to ring.

If you did the same for your son, (who also has multiple devices), all his Echoes in his house would ring until he accepted or rejected the incoming call from you.  I don't think you can target a specific device in his home because it is outside your account profile and you aren't electronically privy to what he calls his devices (Naked Lady Room, etc.)

Disclaimer: I have done the intercom thing in my own home.  I've not used the call somebody else feature, but I've read about it and what I've described seems accurate.

[Gee]

No answer but a supposition :

I thought a call would be dropped and reachable on all echos linked to a specific account (in fact, I though I could even listen to a dropped call from my phone on the Alexa app) but from what I understand, the call you made to your son went to his "office echo" specifically. Just a thought but maybe this is because it is the last echo he talked to before your call was dropped (?)