Hi,
You can achieve this with HikaShop's custom field conditions. Here is the approach:
1. Create a custom field of type "dropdown" on the address (for example "Customer type") with two values: "Retail" and "Wholesale".
2. On each of your business-specific custom fields (company name, tax ID, etc.), go to the "Display limited to" option and select your "Customer type" field as the parent field, then select the value "Wholesale". This way, these fields will only appear when the customer selects "Wholesale" in the dropdown. You can find more details about this option in our documentation:
www.hikashop.com/support/documentation/4...shop-field-form.html
3. When a customer selects "Retail", they will only see the basic fields. When they select "Wholesale", the additional business fields will appear dynamically.
For automatically assigning the correct Joomla user group at registration, you can use the "User group on registration" setting in HikaShop's System > Configuration, under the Checkout tab.
www.hikashop.com/support/documentation/5....html#checkout_login
For the non-HikaShop areas of your site, we would recommend keeping the "Redirect Joomla registration to HikaShop" plugin active everywhere so that all registrations go through the same HikaShop form. Retail customers will have a simple form since the wholesale fields will be hidden.