Dear Xmanhattan, thank you for your answer.
Check this solution for my previous question:
It needs to modify the source code in 3 files:
By default Elxis allows only super admins (group id = 62) to login that way. You have to enter the id of the other group too in the source code.
Setting the website in this way you allow more that one group of people to access the page after login.
Actually the eblog accept only super admins. I don't know if is related or not to the main configuration reported above.
I am interesting in allow guest to see the blog. Actually the site is setted as offline but if you have a kind of account you can access but only when you want to comment or interact to the eblog or website that you need an account.