How to display and Handle two different forms with overlapping element?

I have two forms of which some elements overlap.

I was wondering how should I approach the situation, there is a possibility to use tabs, one for the common fields and other two for the corresponding form elements for different categories. Other option is I can save the common elements in a temporary database on 'Next' button click then present the relevant form based on the selection of the category in the previous page. What else can I do ?

Sorry if I wasn't clear the first time.

Let me try to explain with an example, say I have a signup page. And my website supports two kind of users, user A and user B, if user A wants to signup he/she has to fill signup Form A and likewise user B fills up signup Form B. Since both of these users are of different type(different role on the website) they provide different kind of information(elements) to signup with. But some information(elements) is common on both the forms, for example like : Name, Email etc. The actual forms are big and complex and ask complex data from the users of both types but some information they ask are similar. And I don't want to make two different forms with some of the same elements.