Yes, GJ auto integration included with GJ. We have a tutorial of exactly this usecase below.

www.joomlapolis.com/support/tutorials/107-use-cases/18331-on-the-fly-creation-of-groups-based-on-registration-data

1) During registration we want to ask to join a group or create a group

Add a radio field with 2 options, join or create. Then use CB Conditional to show a Auto Join field from GJ Auto Integration (once installed create the field in Field Management) if the radio is set to join a field or a text field and textarea field to create one then create it using GJ Auto Integration in a new Auto with the after registration trigger.

3) Auto login and redirect them to a specific URL

You can use a login action within CB Auto Action to log them in. It can also do a redirect with the login. As for redirecting to the group they just joined/created I guess a CB Query Field to grab what they created/joined then sending them there could be used to format the URL with the group id.

None of this is a simple task. Nor is there a tutorial for it, please understand you'll need to do extensive testing and "playing" with GJ Auto Integration and CB Auto Actions to accomplish this.

If the radio field value is Join then display a Join field (from GJ Auto Integration). If the radio field value is Create then display a Text field and Textarea field (title and description) then create it using the GJ Auto Integration with the after registration trigger (tutorial linked above describes this usage).