PGF and TikZ -- Graphic systems for TeX

Hello,

I want to create a chain, in which node distance=0, but every 4th node is separated (e.g. distance=10mm), and has a join.

the first part (distances) I was able to implement this way (there has to be something easier, though...):

  \path[draw, start chain=bucket
    going {at=(\tikzchainprevious),
           xshift={(6mm + 10mm * (mod(\tikzchaincount, 4) == 1))}},
    every node/.style={draw, minimum size=6mm},
    every join/.style={->}]
\foreach \x in {31,35,7,11,12,13,14,51,22,22,33,44,66}
{
  node[on chain] {\x}
};

but for the join I couldn't figure it out. If it matters, I'm using cvs version. Any ideas?

Thanks, Orgad