Connecting multiple computer speakers?

audio receivers usually connect to speakers by speaker wires, not by RCA, so you would not be able to hook it up by 3.5mm to RCA adapters directly. Receivers may have pre-outs which are RCA based, but I don't think those are amplified and won't be loud enough.

I think 3.5mm speakers usually come with their own amp which is built into a subwoofer, which is then connected to one PC and one PC only by 3.5mm cables. Multiple PCs mean multiple amps. If you want to use multiple devices with such speakers, I can only think of splitters. You will have more wires, but you may or may not notice a difference in quality. Maybe you can give it a try.

With a audio receiver, what people do is connect all their devices to one receiver, and the receiver outputs audio to a set of speakers that use speaker wire. Also you said you have multiple computers, which means 2 different audio sources. That will work with a receiver if you only need one desktop to have audio at once.

Well - if you run the same signal to more than one of the 3.5 mm jacks - each jack gets 50% of the signal.

This is usually fine but splitting it 4 ways could be a problem.

Audio Receivers are home theater receivers. These are not usually compatible with computer speakers which use the 3.5mm jacks.

(Your Bose speakers each have their own AC power cord - right?)

What you basically want is a switch box that uses 3.5 mm jacks or RCA jacks.

I have not been able to find such a thing on Amazon. I did find a switch box that uses some RCA and some 3.5mm jacks which you can use adapters for the RCA jacks.

I bought a "Hopewell" small switch which has 3.5 mm jacks in a common-buss design. I have 1 set of computer speakers but 2 PC's and a tablet and the switch lets me let the speakers listen to all 3 devices or I can disable any one with a button press. It's about $20. If you got 2 of them you could use 1 to manage the source devices and feed the second switch which manages 3 of your speaker sets. You need a 3.5mm male to 3.5 mm male cable to connect the two.

Beyond that.. I dont know what else to suggest.