Determining Capacitance between Multiple Conductors

Hi,

I have a system with 3 conductors as in the attached image. The first (left) conductor is set to a terminal boundary with V = 1. The second (right) conductor is set to a terminal boundary with V = 0. The last one (the floating conductor) is set to floating potential with Q0 = 0.

However, I'm not able to measure the capacitance between terminal 1 or 2 and the floating conductor (the only options are C11, C12, C21, C22). What boundary condition should I be using on the floating conductor to allow me to measure the capacitance?

Thanks,
Chris