Yes you can connect multiple USRP devices in the same host machine and control them with the same MATLAB session. But you will need to write the MATLAB code (e.g., script) that uses them according to your goal.
I assume that you are going after multi-radio operation. You could enable a multi-channel operation with a single USRP radio, as its center frequency can vary during simulation (i.e., it is tunable).
