It is possible to have more than one shipping quote working at a time, however how you want it implemented will determine what steps you need to take.
If you would like your user to be able to select one shipping provider versus another you can add a select list, then on the confirm page you set the value for the $WAGLOBAL_Shipping variable depending on what the user selects. You can also make is so both are applied in the cart. Please describe what you would like to have in place from the perspective of the user so we can help you get it going.