Drops can self-organize in two-dimensional (2D) microchannels to form ordered arrangements. Design of microchannels that result in a particular pattern of drops for a specific purpose is difficult and nonintuitive due to the inherent complexity of the drop dynamics. We address the problem of understanding the arrangement of composite drops inside a microchannel. A multiagent modeling strategy that was recently proposed by us is employed to understand this complex design problem. We consider the design of a drop drop contactor that results in an equal mix of A and B. We seek to find the inlet sequence of drops A and B that would result in the maximum contact between A and B in the ordered arrangement. We find that intuition-based results work well only for a single layer arrangement of drops. We attribute this anomalous behavior to the symmetry breaking instability of the drop patterns in these 2D microchannels. From the dynamic simulations, we understand why certain inlet sequences perform better than others. We then discuss the use of the simulation strategy in several possible design problems.