According to Amazon, you can use any supported Amazon Echo device, such as an Echo, Echo Show, or Echo Plus, to simultaneously communicate with others through all the Echo devices in your house. Previously, Drop In messages could only be sent to from one Alexa-enabled device to another. For instance, one user in the kitchen could “Drop In” on a second device in the living room.
Amazon's Drop In feature also worked with your Alexa contacts, so you could send a "Drop In" message from the Echo in your bedroom to your grandma's Echo Show in her house. When anyone receives a Drop In, the light indicator on the recipient Echo device pulses green, and you auto-connect to the contact. Now, because this feature works across multiple Echo devices, it's handy for groups.
To start a group Drop In conversation, ask Alexa to “Drop In everywhere.”
Imagine asking your household something like, "What does everyone want for dinner?", with your message being blasted through to the Echos in every room in your home, allowing anyone in those rooms to easily respond. Technically, Amazon also offers a broadcast feature, which has similar functionality, in that you can record a message and broadcast it across your devices a moment later.
Amazon said users in the US can also now set reminders to play across all their Alexa devices. In the Amazon Alexa app, choose “All devices” when creating a reminder or enable the feature for all reminders by going to Settings > Reminders and opting into “Announce on all devices.”
For more Alexa tips and tricks, see our guide.