Difficulty in understanding Interface parameter in Access restrictions

Difficulty in understanding Interface parameter in Access restrictions

hello there,
i have been trying to get a thorough understanding of the " interface " parameter in the Access Restrictions section. i have already read the description which is given in the info  button in interface parameter and i have referred and read the document as well.
As per my  understanding if i have 2 interfaces in my system and i want to make the safesquid listen on only one interface i have to specify the IP of the network interface followed by the : and port on which we want safesquid listen to.
i have tried like that as well. heres the screenshot of it.


and here's a screenshot of my safesquid server's interfaces.


but when i do this, the web request comes out of the RUSHIKESH GROUP user group. here's a screenshot of it.




this is the understanding i have of the interface entry. Please tell me if my understanding is correct or not and if its not please tell me how the interface entry actually works.