ERC (CM) have nothing to do with developing a morph. It is only a way of "turning" the dial of one morph (or channel) by turning the dial another morph (or channel). Compose will do a super peachy job of isolating a group or any combination of groups. It will not magically convert the rCollar of Vicki into the rCollar of the bikini. A morph is the group it works on. The number of verts and how they are linked is identical. The only difference is where the verts are in space. For a morph to work, it has to BE the group it morphs.