I think generally speaking you'd use a "Matlab function" inside simulink and just feed it IO's. Hope that helps?

i have tried that but with very limited success..  

i am very much unable to make my problem understandable to the GA block.

So need a little more help on that. 

Dear Faruk Poyen,

Try to run GA using script and call this script file in simulink block. For GA as script file, see (answer by me) the link given below:

https://www.researchgate.net/post/When_I_using_GA_solver_it_displays_Too_many_output_arguments_why