Nested rules in forward chaining mode?

[franswors...@googlemail.com]

When I want to make sure that a certain rules is executed before another 
one I am storing them in seperate rules files, instatiate a RuleReasoner 
per file and pass the inferred model on to next reasoner.

Therefore I'd like to know if it is possible to define rules that, only 
if true, invoke other rules or to define nested rules (in forward 
chaining mode) like this:

[rule: (?x :hasY ?y) (?y :hasZ ?z)

          ->
          (?x :hasZ ?z)

        [rule2:
                (?x :hasP ?p) (?p :hasA ?a)
                ->
                (?x :hasA ?a)
        ]
]