configure pro sites for two different types of users

I have a site that has two different user groups. for group 1, i would like the sign up to be free. maybe there us 1 premium version, so lets say 2 possible account options for group 1.

for group 2, which is for professionals, it would have 3 account options. one is free and would tie into a professional directory. the other options would have increasing functionality for different paid levels.

the question is how can i present the right sign up path for the right user type. it seems i need an option at sign up for the user to pick the account type and option. however, i almost need two set ups for the pro plugin, unless there is a way to create multiple sign up paths.

thanks