What Planck said is true, but there might be a way around it. You could try grouping the civilian to a high ranking resistance officer, set the officer's probablity of presence to 0, and setcaptive true the civilian. Then, when the civilian joins resistance, setcaptive false him.
Just an idea, I'm not sure how feasible it is. Will units enemy to resistace still target a captive unit, but not shoot?