How can a group-dream machine from Christopher Nolan's "Inception" be built?

Imagine that anything going on in the world is interpreted by our consciousness to create our own vision which is similar to other visions but still not very much the same.

The consciousness seems to be collecting all of the perception sources into one channel. This is how we describe complicated things in simple words.

The machine intervenes in this channel and redirects it to where all of the channels gather in one common perception flow.

When sleeping, we do not get things from outside but we get them from inside. Perception channels are still there but they more likely resemble rings than beams.

Thus, the machine simply collects all the rings to create a single contact point becoming a place where we find ourselves again.