Important Echoplex Brother Syncing question

["Bryce Avary" <bryceavary@gmail.com>]

Hey guys,
Recently I purchased 4 echoplex digital pros with 4 foot switches.  I
am in a full time touring band and am about to incorporate a looping
section in our set where I start on the drums record a beat, then
bass, then guitar/keys etc making a song in front of the crowd from
scratch.  Yesterday when I opened my new echoplexes i turned them on
and started looping and having not synced them up at all, I found that
it worked but it could easily sound just a hair off.  I read in the
manual that by using the brother sync and y cables you can hook up
many echo plexes and have it be sound tight.  However it doesnt show
how to hook up more than just one.  So my question is,

If you have 4 echo plexes that you want all synced together, how do
you hook them up to eachother and using what cables?

I have contacted gibson and other people and have yet to hear back
from anyone.  If anyone knows this answer, I would be forever grateful
as we are in a time crunch!  Thanks so much!