Automatic Group Member depending on fields in profile

Hello there,

I am looking to solve the following problem:

In our memebers profile (for a fan club) you choose at registration which artists you support -

a,
b,
c,
d,
etc...

After logging in, there are also the respective groups for these musicians...

How can I coordinate that, depending on which artist you select in your profile upon registration (or after registering), you automatically become a member of that respective group?

Thanks for the help!