subviewだけtouchできるview

gistfile1.m

@interface TestView : UIView
@end

@implementation TestView

- (UIView *)hitTest:(CGPoint)point withEvent:(UIEvent *)event
{
    UIView *view = [super hitTest:point withEvent:event];
    if(view == self) {
        return nil;
    }

    return view;
}

@end