Using party chain function on Sony Speakers?

Some experts are needed here!

I bought Sony speakers GTK-X1BT just recently. It has 1 function called party chain which it allows me to "connect multiple audio systems in a chain". So I try to connect my Sony speaker with my other non-party chain speaker. But the party chain function only works when I play music from my computer/iphone via Bluetooth. The set up is My computer/iphone (bluetooth) -> Sony (Party chain audio out) -> other speaker (audio in).

However, when I tried to connect my Sony to my computer or my DJ controller Pioneer Ergo V via audio cable, the music only come out the Sony speaker, not the other speaker. The set up is My computer/Pioneer Ergo V (master out) -> Sony (Party chain In) / (party chain out) -> other speaker (audio in).

The reason why I try to have Party chain by connect computer to Sony speaker via audio cable because when I use Bluetooth, there's a small delay when I do music mixing on my computer, let say I press play, a micro second later the music coming out of the speaker. Which really affects my mixing experience.

Could someone tell me is it something I do wrong, or it is just the way party chain works, only when playing music via Bluetooth?

That feature only supports other Sony speakers with the feature, it does not support other speaker brand or models

it has coding that only recognizes other party chain enabled speakers, its Sony's way of selling you more speakers, even some other sony bluetooth speakers don't support it as they don't have the ability to multi synch to more than one device, in fact not many devices support multi synch at all other than some headsets and gaming headphones