Specific user group assignment during registration

-- HikaShop version -- : 4.2.0
-- Joomla version -- : 3.4.1
-- PHP version -- : 5.5.23

Hi out there,

I posted my problem in a different section already. This is what I wrote:

Is there a way to set the user group on registration by entering a given code/text during the process?
A selection of products should only be available to a user group. In this case it's different schools that should only see the collection of their own school.
Now I want to hand out a code (text) to the school, so that when entering this during the registration process they are automatically put into the right user group.
I know there is a tool to select the user group, but I don't want everyone to see who my customers are.

One answer was:

---

Otherwise, you can see to use a user custom field which will be display during the registration and then, using a little custom plugin, you can change the user group after the user creation (depending the content of the custom field).
So, it would be more something like a pass-code to unlock the user group.

I was asked to post my problem into this section.
As far as I can see, the "User Group FTW For Hikashop" comes very close to my problem.
Is there anyone to code a little plugin?

Thanks in advance!

Yours,
Daniela

Dear Daniela,

We are a web development company located in New Delhi, India and we'll be more than happy to do this customization for you. Please send me an email and then I'll provide you time and cost estimates.

Dear Daniela,

Thanks for choosing us for this project. Please leave your feedback for us on www.hikashop.com/forum/9-commercial-jobs...s-are-available.html

Regards,
Sanjay Kumar