I think what he's asking is he wants certain weapons to only be used in the right hand while other weapons can only be used in the left hand.
If that's it, then I'm afraid it's not immediately possible. There are no options for this specifically.
However, one way of working around this would be to prevent equiping of certain weapons in a specific hand through their weapon script. You should be able to detect if said weapon is equipped in right hand or left hand, then execute actions based on what hand it has been equipped to. I haven't actually made anything for FPSC in quite a long time now, so I can't come up with anything specific. Hopefully one of the PB scripters will pop in to help me out here.
The one and only,