There are a number of ways it could be done - a little research would be required.
Right now, the expanders are slave devices. If the Ansible acted as a master, it could request the values of the four knobs at some reasonable frequency. i2c busses can support multiple masters - but I’m not sure offhand if the Ansible’s chip and underlying AVR library allows it to be both a master and a slave.
Another way would be to modify the TXi firmware to act as a Master and to send out values to Ansible when a knob changes position. This way the Ansible can stay as a slave and i2c chatter would be minimized. This would be a fairly trivial firmware modification for the TXi. I’d be happy to do it if someone was working on the ES port.