Are the Google, Youtube, Blogger API Linked Somehow?

If I have a user log in to my site with their Google account, using the OAuth2 method, can I use that token to get the users Youtube/Blogger info if they have those accounts linked?

I've read the Youtube and Blogger API's and they both use AuthSub, and are currently compatible with version 2 and older, while Google is version 3.

Do I have to make separate log ins for Blogger a开发者_开发知识库nd Youtube or is it possible to retrieve that info from the logged in Google account by adding the two scopes to the Google permissions somehow?

Thanks,

Goran