How to change simulink block settings using a input selection parameter

I have a simulation model which is to be be used for multiple variants and environments. The model block parameters are dependent on environment and variants. Meaning,when the environment changes the simulation block parameters have to change to accommodate for the changes. I would like to change, for few of these blocks,the block parameters using a input switch.

For Eg: If switch is 1 then set a[1],b[1],c[1],d[1],e[1],f[1] as block paramters and if switch value changes then set as per the switch value. I wanted to build this model and generate code out of this. As this switching will happen when the model is running a real time processor. Would like to know,what is the best way possible to implement this. If it was only simulink then the task would have been easier, but as this is on a processor, i have no clue as to how to go about it.

I welcome any suggestions on this!