Kind of difficult to explain thats why I gave an example, load the example into designer and check out how I set it up. Basically I set the group I want to have expand into its own subform.  Make sure the subform height is set as expand to fit and that all of the text fields are set as expand to fit...

Cornyo,I made a quick example based off the form you attached.  I am assuming that my example is one of the spots you would like the ability for content to expand.