2 arduinos listening to a single Onewire sensor

I know that onewire devices use a bus to allow for multiple sensors on a single pin... But I'm trying to do the reverse. I have a single Onewire sensor (ds18b20) and I want two controllers to have access to read the temp.
I am trying to hack a polyscience sous vide. It already has the sensor inside, and their own proprietary microcontroller listenkng to the sensor. I was hoping to split the vcc, gnd and signal wires and have one set go to the existing mcu and the second going to mine where I could simply listen to the temp...
Any thoughts?

If you look at the datasheet on page 9, Fig. 10 shows the connection to one microcontroller. A second one can be connected in parallel if one is the master and signals the other micro that he can have the com-channel. The second one give then an acknowledgement to the master. So the two micros have to synchronize themselves via two IO-pins to avoid a bus conflict. After reset the micros IO-ports are usually in input mode and you can look at the check-list for interfacing in this application: http://ichaus.biz/wp1_mcu_interface on page 2.