How to dynamically change KDC server and other parms

[Veeru]

Hi,
  We have a plugin program that authenticates user based on kerberos
principals. The KDC server and realms can be set using the UI and so we
are using the following :

      System.setProperty( "java.security.krb5.realm",
getKerberosRealm() );
      System.setProperty( "java.security.krb5.kdc",
getKerberosKDCServer() );

My question is : Since these are not thread safe, What can we do if
there are two  JSP's using two different KDC but using the same plugin
for authentication ? i.e. how do we gaurantee that the request goes to
the expected KDC ?.

Thanks in advance,
/Veeru.