When you are replicating a website, you can :
- verify that you have the correct page title that appears in the "administrator" login form.
- Once you are logged as administrator, you can again check that you are using the correct DB connection and table prefix when you go in Joomla Global Configuration.
- You can also use the JMS tools to check the table created and review the slave site DB parameters and tables
- You can also use a tool like PHPMyAdmin to check that you have the correct table prefix created for the slave site.

If finally, the DB is correctly populated and that you arrive to the wrong administrator login website (master instead of the slave), then you have to check that you have spelled the domain name correctly in the list of slave site.

When I compare the administrator login form between the www...com/joomla/administrator and www...com/joomla/us/administrator , I see that you have the same page title "international USA".

I don't know if you have selected "share the whole site" or not in the JMS template.
In most frequent case, this parameter is not required because this does NOT replicate but only create a new "configuration.php" files with the same DB connection paramter (including table prefix).

Your problem is not related to different users.
Why don't you try to apply the sample present in the tutorial step 16.
This not only show you how to create a fresh slave site but also how to replicate it and also share part of the content (in this case the users).
So if you don't select any sharing things in the JMS template / sharing panel, this will replicate the website.
Perhaps this will help you understand how to use the JMS templates functinoality.

The replication of a website suppose that you have defined a JMS template.
When there is no "JMS template" defined then you can not select any "template site" in the JMS manager"

The JMS template is used to define the way you replicate a website.
This is in the "JMS template" that you defined which website you want to replicate and that you also define the generic rules for the replication using keywords. The usage of keywords is usefull when you propopse the website replication from the front-end.

Why don't you try apply exactly the sample that is provided in the tutorial step 16.
tutorial.jms2win.info/jms12x/usersharing/index.html

If you follow exactly the procedure you will learn how to create a fresh slave site but also how to replicate a website with user sharing.

Once you will have understood how to use it with "sub-directory" as presented in the tutorial, you could retry apply it with domain name or sub-domain or event in other specific sub-directory.

I hope this will help you as this video also present the concept of the replication and sharing.