According to some embodiments, a stacking assembly accepts mail-pieces traveling from a re-direct mechanism in a first direction and urges a leading edge portion of a mail-piece toward a registration wall of a sortation bin. The stacking assembly may include a plurality of neighboring cam shafts, each with at least one cam, arranged along the first direction, such that rotation of the cam shafts results in synchronized rotation of the cams to guide an incoming mail-piece. Rotation of the cam shafts may also urge a previously stacked mail-piece away from the cams, and into the sortation bin, in a second direction perpendicular to the first direction.