Grails - J2ee integration

Hi All,

I wish to do very simple thing -

In one of the divs in a JSP of my existing J2ee application I wish to render a grails app(ajax based).I  could achieve this by simply using an iFrame,but I dodnot wish to use it for performance reasons.Is there any other way out

Please note that the J2ee app and grails app are on 2 different servers.

Any pointers would be very helpful

Thanks In Advance
Regards,
Ruchi