Would example like this help?
Names Default To Here(1);
//radiobox variables
enableList = {2,5};
rbItems = {"one", "two", "three", "four", "five"};
rb = Radio Box(rbItems);
//start as all disabled
For(i = 1, i <= N Items(rb << get items), i++,
	rb << enable item(i,0);
);
//enable based on enableList
For(i = 1, i <= N Items(enableList), i++,
	rb << enable item(enableList[i],1);
);
//change first selection to first in enableList (otherwise will be first in rbItems)
rb << Set(enableList[1], 1);
//create modal
ok_pressed = 0;
ex = New Window("Dialog() example",
	<<Modal,
	V List Box(
		rb,
		H List Box(
			Button Box("OK", ok_pressed = 1; rbSelection = rb << get),
			Button Box("Cancel", ok_pressed = 0)
		)
	)
);
If(ok_pressed == 1,
	show(rbSelection);
	show(rbItems[rbSelection]);
);
					
				
			
			
				
	-Jarmo