Does this plugin have hooks and filter?

Hello there,
Does this plugin provides hooks and filter?
Currently, I have added two different groups in my two sites. unregistered group registered group

How it was supposed to work was:
If user subscribe from 1st site (without signing in), he will be assigned to unregistered group.
If is automatically get subscribed, after registering, he will be assigned to registered group.

But unfortunately, registration and subscription goes under same site. So user will be registered to unregistered group.

Now I need to know if there is any hooks or filter that is triggered before or after marking user as subscriber right after he is subscribed. Or do you recommend any other idea?