Ideally, the multiple small transistors should operate like one large transistor. Realistically, it all depends on how the transistor parameters and parasitics scale. In the case with multiple transistors, each device will see a integer portion of the current in the large device. So if everything scales linearly, then operation should be identical. However, I doubt if this is the case! Device parameters are probably nonlinear function of the bias voltages and currents, so you will probably get different behavior. But depending on how strong the nonlinearity is the results may be close. Just try it and beware of the results.
Best regards,
v_c