p2p transmission between devices

I have a question about differences between syncthing and resilio sync whether syncthing supports p2p transmission between devices that have been trusted to a same parent device and shared same directory but no trusted by each other when syncing files like resilio sync or qBittorrent.

No. But the introducer feature can be used to let those two “child” devices peer with each other as well.

Thanks for you reply. One more question, is a folder shared by some devices split into several meta files and syncing by those devices at the same time, or just syncing by a center devices as a whole directory?

I’m not sure what that means, but files in a folder are synced individually, some of them concurrently.

Like resilio sync or qBittorren, a folder or big file could be syncing with several nodes or devices.

Yes

So the files in folder could be syncing with several devices at the same time to divide the network press of center device in p2p network.

Again, yes.