(1) If a third party has filed a notice of intention
to defend, this part applies, with necessary changes, as if the third party
were a defendant.
(2) If a person joined as a party (a
"fourth party" ) by a third party has filed a notice of intention to defend,
this part as applied by this rule must have effect as regards the fourth party
and any other further person or persons included and so on successively.
