[R] S4: Multiple inheritance

[Christophe Genolini]

Hi all,

Working with S4 object, I definine two class foo1 and foo2. I define '[' 
(resp. '[<-') for the two classes.
Then I define a third class foo3 that inherit from both foo1 and foo2.
Is there a way to make '[' (resp. '[<-') for foo3 inherit from '[' 
(resp. '[<-')  for foo1 and foo2?

Thanks
Christophe