amwfc - 2014-06-02

Is it possible to achieve fork down style of edges with graphs as with child nodes?
I would like to reproduce the following MWE but using graphs (to avoid extensive calculation of node positions). 

\documentclass[10pt,landscape,ansibpaper]{article}
\usepackage{tikz}

\usepackage{geometry}
\geometry{
    left=2em,
    right=2em,
    top=2em,
    bottom=2em,
}

\usetikzlibrary{trees}
\tikzstyle{every node}=[draw=black, thin, minimum height=3em]

\begin{document}
\footnotesize
\begin{tikzpicture}[
    supervisor/.style={%
        text centered, text width=12em,
        text=black
    },
    teammate/.style={%
        text centered, text width=12em,
        text=black
    },
    subordinate/.style={%
        grow=down,
        xshift=-3.2em, % Horizontal position of the child node
        text centered, text width=12em,
        edge from parent path={(\tikzparentnode.205) |- (\tikzchildnode.west)}
    },
    level1/.style ={level distance=4em,anchor=west},
    level2/.style ={level distance=8em,anchor=west},
    level3/.style ={level distance=12em,anchor=west},
    level4/.style ={level distance=16em,anchor=west},
    level 1/.style={edge from parent fork down,sibling distance=40em,level distance=5em},
    level 2/.style={edge from parent fork down,sibling distance=16em,level distance=5em}
]
    \node[anchor=south,supervisor](super){Supervisor\\Supervisory position\\Location}[]
    child{node [teammate] {Teammate6\\Position4\\Location4}
        child{node [teammate] {Teammate61\\Position4\\Location4}
            child[subordinate,level1] {node {Subordinate161}}
            child[subordinate,level2] {node {Subordinate261}}}
        child{node [teammate] {Teammate62\\Position4\\Location4}
            child[subordinate,level1] {node {Subordinate162}}
            child[subordinate,level2] {node {Subordinate262}}}  
        child{node [teammate] {Teammate62\\Position4\\Location4}
            child[subordinate,level1] {node {Subordinate162}}
            child[subordinate,level2] {node {Subordinate262}}}  
    }
    child{node [teammate] {Teammate7\\Position5\\Location5}
        child{node [teammate] {Teammate7\\Position5\\Location5}
            child[subordinate,level1] {node {First\\Subordinate}}
            child[subordinate,level2] {node {Subordinate2}}
            child[subordinate,level3] {node {Third\\Teammate}}
            child[subordinate,level4] {node {Longtext-\\teammate}}}
        child{node [teammate] {Teammate7\\Position5\\Location5}
            child[subordinate,level1] {node {First\\Subordinate}}
            child[subordinate,level2] {node {Subordinate2}}
            child[subordinate,level3] {node {Third\\Teammate}}
            child[subordinate,level4] {node {Longtext-\\teammate}}}
    };

\end{tikzpicture}

\end{document}