Modify User Interface of installer when msi runs using c#

Question

Hi,
   I am pretty new to c# coding and have a doubt. I am creating a windows setup project.In it, i have 2 dialog boxes, apart from the usual ones. In the first dialog box, i have 3 radio button ( say, a, b and c ). In the 2nd dialog box,  have two checkboxes ( say chk1 and chk2 ). Now what i want is that, when a user runs the msi installer, then chk2 should be enabled only when radiobutton a is selected and should be disabled otherwise. No action is required for the other checkbox chk1. I should say in this context that the checkbox dialog box just follows the radio button dialog.
Any help is welcome! Thanks a lot in advance.
Subhrochit.