We have used dissipative particle dynamics (DPD) to simulate the self-assembling behavior of A-block-(B-graft-C) coil-comb molecules, in which each B segment is covalently bonded with one C segment. In addition to the composition, we found that by varying any of the interaction parameters between each pair of components I and J, where 1, J = A, B, C, we can also induce a series of morphology transitions associated with two length scales. Moreover, we observed that if the length of the BC-comb block is not long enough, the resulting morphology is mainly in the large-length-scale, ordering between the A-rich and C-rich domains with most of the B in the interfaces. By increasing the length of the BC-comb block, one may expect that both B and C can pack orderly to form a lamellar structure. As a result, various experimentally observed structure-within-structures have been simulated via DPD.