An integrated circuit includes a middle active-region structure between a group-one active-region structure and a group-two active-region structure. The integrated circuit also includes a main circuit, a group-one circuit, and a group-two circuit. The main circuit includes at least one boundary gate-conductor intersecting the middle active-region structure. The group-one circuit includes a group-one isolation structure separating the group-one active-region structure into a first part in the group-one circuit and a second part in a first adjacent circuit. The group-two circuit includes a group-two isolation structure separating the group-two active-region structure into a first part in the group-two circuit and a second part in a second adjacent circuit.