I don't think that is easly done with CAN communication. You have a clock line and a data line. You don't have to drive the data line if you want to talk on it, you only have to pull down. So you can't simply not connect a wire (as in a Rx/Tx configuration) but you have to make the sillicon chip unable to Tx. This requires new sillicon chips, and even then I don't know how well they can pull it off. So this solution is far from trivial.
There is no clock, that is one of the genius aspects of CAN. There were earlier ideas about multiplexing before CAN and they needed a clock, and that is why they never worked right.
