mappping two ontologies

[aarthi]

hi i have two ontology.. consider ont1 and ont2. if both ont1 and ont2
have a class named employee. And ont1's employee class have a sub
class named age. but ont2's employee class doesn't have that class. i
need to specify a relation that age "is-a" subclass of ont2's employee
class. how to do that using jena? anyone help  me