Depends on how the hydraulic ports are plumbed... If you can post a photo of what the lines go to, might help.
I'm going to assume it's a diverter valve.... So if you follow the hydraulic lines back from the front. I'm guessing they go to a diverter valve, with 6 lines. 2 going in, two going to the grapple and 2 to either the lift or curl cylinders... (need to know which one) because once you press the button, the lift or the curl will not work but the grapple will.
Most likely you just need the grapple to have the same connector as the hydraulic ports that you have and you should be in business.