Question about multiple sql databases!

[Haviaras Kostas]

Hello, I have define three sql databases on the sql.conf and each database
point to different database but they have the same username and password.
Each of them I have added on the /sites-enabled/default instead of the sql.
My problem, when I connect to one through the my NAS its connect
simultaneously on the 3 databases. Even if the username is doesn't exist on
the other 2.
Here is my config:
sql.conf:
sql db1{

}
sql db2{

}
sql db3{

}
default(replace each sql with the following three):
db1
db2
db3


I have to create Realms? Or 3 differents virtual servers? Thanks