How to achieve the following in Cypher query?

How to achieve the following in Cypher query?

Requirement

(sn)-[* AND not via tn]-(ptn)--(tn)
(tn)-[* AND not via any of the ptn nodes]-(pfn)
(fn)=(pfn)without(ptn)
Where

sn : source node
tn : target node
ptn : pre target node(s)
pfn : pre final node(s)
fn : final node(s)
for example consider the data @ http://goo.gl/Ou2GZG
expected (ptn) at line 01 : node 3, 7
expected (pfn) at line 02 : node 3, 7, 6
expected (fn) at line 03 : node 6