I log in to Stack Exchange family of sites via OpenID.
So, if I login to, say, https://meta.stackexchange.com/, then I can just open the list of sites:
But, if I'm logged at say, https://meta.stackexchange.com/ and I try to click on a site from this list which is not a subdomain, such as https://superuser.com/ - then I am not logged in automatically, I have to enter my OpenID and authenticate again.
The same happens also in my usual workflow - usually I log in to Stack Overflow first, and then afterwards sometimes I need to log in to Unix/Linux; but if I click on Unix/Linux from the SO list of sites, then I am not logged in automatically, and I have to enter my OpenID and authenticate again.
Is it possible to somehow have me logged in automatically to other Stack Exchange sites - subdomains or not - if I am already logged in via OpenID to Stack Overflow?