Carlos
This feature was not actually design in the API. So, it is not something you could obtain directly from the API.
Now, maybe a trick like making the state as output by modifying the model and try to apply constraint on that output could be possible. However, I am not sure how 'secure' this option would be since you could have coupling within the states and, most important, I am not sure if the solver would be able to have those additional constraints and be able to solve it.
Hope this helps,
Barp - Control, Simulation, RTT and HIL - National Instruments