additional create account fields for wholesale customer

I don't know if this is right forum for this question but here goes ...

I'm helping someone with a site that has retail customers and wholesale customers. Both can browse without seeing prices, but must login to see prices and purchase. I need to change the create account process so that customers let me know if they are retail or wholesale. (a radio button would be fine) After completing the standard create account form, I have 9 additional questions I want answered by wholesalers. How do I accomplish this? After the wholesalers complete the second set of questions, I want the same process to continue as the retail customers -- welcome email, etc.

Suggestions on how to move forward with this would help. The site used to be divided into a .com (wholesale) and a .biz (retail). Now it's been combined into one. I had helped get additional questions on the .com site's create account page but now that they're together, I need to figure out how best to let the retail customers "move on" while getting the wholesalers to complete the additional fields.

Thanks for assistance!

Sorry! Just got some clarification from my friend. Wholesale customers have to be APPROVED to purchase, but retail customers can purchase once they're logged in. That I'm sure just made things quite a bit more challenging, huh?

To clarify:
Retail and wholesale can browse.
Retail must login to purchase and account does not require approval.
Wholesale customers must login to purchase BUT account requires approval.
Wholesale customers must answer 9 additional questions during create account process.

We've always suggested to our customers that they use yoursiteDOTcom/wholesale or similar. You copy the database, change prices with a sql statement, massage the login slightly, and you have two sites that don't have problems trying to work together. You can put a no follow in the wholesale folder to stop the duplication in search engines.