Registration form radio buttons – link to different login pages

In setting up a New Custom Registration/Profile Field in Registration Profile Fields & Options, I want to use radio buttons for selection from 3 different levels of paid membership – each button needs to point the user to a different landing page – which is a unique authorize.net payment form.

I have a re-direct to the various login welcome pages in the S2Member General Options using this redirect:
http://pets-centralmedia.com/subscribe-level-%%current_user_level%%
but how does the registration form configure and then communicate the various member levels (1, 2, 3) so that a member gets to the right login page?

Is there a method other than radio buttons?

Thanks.

https://wordpress.org/plugins/s2member/