Not if one of the Amp or Era 100 pairs is used for surround.   

Thanks - I would be looking to purchase 1 Era 100 which would be for music only from a streaming service.   I would hope that I can group the pair of in-ceiling speakers with that era 100.     

I would also hope to pair the Sonos Beam with then in-ceiling speakers when I wish to play music.    I do not have a plan to create a surround sound with etc ceiling speakers and the Sonos Beam.   I would play the TV through the Sonos Beam, but through the in-ceiling speakers.

A few things.  If you set them up as 3 “rooms” (rooms is just Sonos parlance for 3 separate zones), you can group them any way you like.  However, you will not get surround sound, and anything grouped while playing a TV source will have a ~70ms delay. 

So it sounds like I should not include the Sonos Beam in any of the “rooms”.   I will have the in-ceiling speakers as Room 1, the era as Room 2 and then a combined area which will included Room 1 and Room 2.

Thanks for any further feedback

In your setup there will be three Rooms: BEAM, ceiling, and ERA 100. Two or all three Rooms can be Grouped to play music. If you Group BEAM with other speakers while watching TV, there will be a delay between BEAM’s TV audio and the other speakers. When playing music all members of a Group will be time aligned. 

If you want to use the ceiling speakers as surrounds you’ll need to “bond” AMP with BEAM to setup a surround Room. At this point you will have two Rooms, surround and ERA 100. In order to return to independent music play you’ll need to remove AMP from the surround system. At this point you will again have three Rooms.

If you are using Trueplay, you’ll need to retune the BEAM/AMP Room(s) after you bond or un-bond the surrounds because Trueplay does not store any previous tunings.