Validating and getting data in QuickForm_controller multi-page form

I am working on a multi-page form. When I transition from the project selection form, I need to validate the data. The user either selected an existing project or entered a new project. I have grouped the two select field and the text field. 1) I need to put a requirement that either one or the other is entered. I also need to do other validation or data insertion. This project information will be used to populate data on later forms. How do I get access to the data? I know it is in a group called project which has two elements projectname and new project. When I dump the variables, I see that they are part of the array. Thanks for any help. Linda