How can I solve a system with differnet subsystem in MATLAB script?

I have a system which is divided in different subsystem and each subsystem is represented by nonlinear state space. I have made the model in simulink but now i want to do this in script and then solve it using fixed time step Runge–Kutta method. The block diagram with each block state variables is given in the figure. I also have complete system matrix as well. Can any one suggest me how to do it :) thnx

 look like this