From page 177 of the Conan Atlantean Edition:
Only characters with levels in certain classes, such as thief or
pirate, or from certain races, such as Zingaran, can make sneak
attacks. A sneak attack can only be made against a character
who is unable to use Dodge Defence or Parry Defence to defend
himself, or who is being flanked. A character who is blinded,
flat-footed, stunned, helpless, the victim of a successful feint,
pinned or being attacked by an invisible opponent can thus be
sneak attacked.
If a character is able to defend himself with either Dodge Defence
or Parry Defence (such as a character with the Refl exive Parry
feat who is attacked when flat-footed) then he is not susceptible
to a sneak attack, unless the sneak attack is of a kind that the
chosen defence cannot help against. For example, a flat-footed
character with Reflexive Parry could still be sneak attacked by a
character using a ranged weapon, because ranged attacks cannot
be parried.
I would say no to your question. They cannot be flanked, at least as I read it.