RS-485 4-wire to 2-wire converter

Question

I'm looking for a way to be able to electrically switch between 4-wire and 2-wire RS-485. Up until now I have used jumper connections to establish both communication ways with one circuit. But I would like to be able to switch electronically (from a MCU). An option would for example be a relay, but I don't have the power capabilities for this. Does any of you know of any known circuits that deal with this issue. A figure to describe this issue:

Answer 1

if you use a "2 wire" RS485 drivers you just need to gate the enable signal.

^{simulate this circuit – Schematic created using CircuitLab}