Yep: set up the Five as a new room, and plug in the cd player (assuming it has a line-out connection). 
 

Then, use the Five’s Line-in as the source. It can play to the Five, or to the stereo-paired Ones, or both together using the Group feature. 
 

If the Ones are set up as surrounds, you’ll also get the sound through the Beam, as you’ll play to a “room” rather than specific speakers. 

Many thanks ​@nik9669a !

I’ll go ahead and find me a Five in that case.

Just to confirm, my pair of Ones are currently set up as a stereo pair with the Beam. I don’t want the Beam active alongside the Five as I’ve heard this is overkill and I can see why that could be the case

Thanks again!

JB

That’s fine. Any room (ie the label used to identify a single speaker, or a stereo pair, or a home theatre setup) can use the line-in from a speaker on the network.
 

In your setup, the Five could be streaming music in one room, whilst its line-in source is used by the Ones. 
 

If you have them all in a single physical room, the Ones plus the Beam and the Five might be overkill

So all these speakers - 2x One, Beam & Five, will be in one physical room (lounge), but I’ll only want the  Five & Ones to play from the CD.

Assume I can make two separate groups, just by creating two rooms. 

However, when you say ‘…line-in source is used by the Ones’ - these don’t have an input right?

Appreciate your help here!

The line in source is a socket on the Five, it can be selected as the audio source for any/all Sonos. 

You will set up multiple Sonos Rooms (dumb name choice) in your room. Each Sonos or bonded set (stereo pair or home theater set) will become a Sonos Room.

You can Group your Rooms together as you wish and then select what source that Group will play.

Thanks both so much for clarifying the plans in my heads with your clear & concise replies!

Just found a refurb Five online as well :)

Best,

JB

If you get tired of swapping CDs look into ripping them into a lossless format, like FLAC, that is easy to convert to other formats with no loss of quality.

Then load them into a NAS or file-share and insert the music library to play them.

Mine CDs are under a bed somewhere and I gave away the CD player years ago.