What's a RGC?
You could use a Norton Amplifier (Current-in voltage-out Amp) where you take the input current through the drain/collector of a MOS/BJT and mirror it through two separate branches invert one of the signals and then convert to voltage. Just be careful with the delays your get through the inverting stage, cause if the delay is significant you might end up with high distortion. To alleviate this you could just add a buffering stage in the non-inverting path that matches the delay of the inverting stage.
Hope this helps,
diemilio