I went to Nayataniloka's Dictionary and there the khandas are listed as:
1 the materiality group khandha rūpa-khandha,
2 the feeling group vedanā-khandha,
3 the perception group saññā-khandha,
4 the mental-construction group sankhāra-khandha,
5 the consciousness-group viññāna-khandha
And the descriptions of the groups is:
What, o Bhikkhus, is the materiality-group? The 4 primary elements mahā-bhūta or dhātu and materiality depending thereon, this is called the materiality-group.
What, o Bhikkhus, is the feeling-group? There are 6 classes of feeling: due to visual contact, to sound contact, to odour contact, to taste contact, to bodily contact, and to mind contact.
What, o Bhikkhus, is the perception-group? There are 6 classes of perception: perception of visual objects, of sounds, of odours, of tastes, of bodily contacts, and of mental contacts.
What, o Bhikkhus, is the group of mental constructions? There are 6 classes of intentional states cetanā with regard to visual objects, to sounds, to odours, to tastes, to bodily contacts and to mind objects.
What, o Bhikkhus, is the consciousness-group? There are 6 classes of consciousness: visual-consciousness, ear-consciousness, nose-consciousness, tongue-consciousness, body-consciousness, and mind-consciousness.
Doesn't really seem like there is overlap here...but maybe I just don't see it.
P.S. Here's the link:http://what-buddha-said.net/library/Bud ... tm#khandha