how to render a response to a specific place on a gsp grails

I am new to grails and groovy. I am trying to find out how to render a response from an action in a grails controller IN THE SAME gsp - but in a DIFFERENT SECTION OF THE gsp - as the gsp that takes the request (in this case a web form gsp page)?

any links or turorials or just straight to the point "do this" kind of replies are welcomed.

I tried to google search for it, but I was not sure what to use as a search term and I could not find a concise answer.

thanks.

ironmantis7x