MIMO on USRP2

Hello everybody.

Now I’m trying to make a MIMO system using 4 USRP2s.
As GNU Radio’s guide, I just followed the Scenario 1,
(http://gnuradio.org/redmine/wiki/gnuradio/USRP2GenFAQ#What-are-the-different-ways-MIMO-can-be-set-up-with-more-than-one-USRP2)
and I was also trying to use
multi_usrp_oscope.py(gnuradio/gnuradio-examples/python/multi_usrp/),
but it was not working.

After that, I was trying to modify multi_usrp_oscope.py to use usrp2
package, but it was not working too.
And I followed source codes which were usrp2.sink_32fc, tx_32fc.
Finally I found a line such as
// FIXME: only one channel right now
in usrp2::impl::impl, usrp2_impl.cc

And I just found a article like Usrp_multi and the USRP2 - GNU Radio - Ruby-Forum,
so what I’m wondering is how I can setup MIMO system using 4 USRP2s
currently.
Is it possible using current version of GNU radio?

I appreciate you beforehand.
Thank you.