Option buttons on a user form

I have two option buttons on a user form named OptionButton1 & OptionButton2. When I select OptionButton1, I want the range name PBITtrigger to be equal to 1, and when I select OptionButton2, I want the range name PBITtrigger to be equal to 2. Can someone help with the code for this?
Thanks in advance.

I have decided to use option buttons in Excel and not on the user form & then link the button to the cell which works fine. I thought when I added the option buttons to the user form, and linked the button to the cell, I would get a value of 1 etc. instead of True. It would be nice to know how to do this when the buttons are on the user form though?

Thank you Joseph. Much appreciated.