nested has_many :through - does Rails supported this at the moment? it seems not

Hi,

Can someone clarify whether Rails current support nested has_many,
:through? For example:

  has_many :business_items, :through => :ai_allocations
  has_many :bi_allocations, :through => :business_items # 2nd one
here references a previous ":through"

I've seen discussion on blogs re support for this but I'm just trying
to clarify whether this is currently in Rails or not. It didn't seem
to work for me when I tried.

i've seen / read those discussions as well (and found it pretty
interesting), but afaik until now it's not a rails feature. last time
i checked it didn't work for me either.

sorry.

thanks