Made-up scenario: S and F are pretty close friends. S invited F over for dinner. F takes her sisters along to S‘s place, knowing for sure that S wouldn’t have a problem with it.
Can F do that? Let’s see..
I found the Prophet in the mosque along with some people. He said to me, “Did Abu Talha send you?” I said, “Yes”. He said, “For a meal?” I said, “Yes.” Then he said to his companions, “Get up.” They set out and I was ahead of them.
Yeah. F may do that. One condition: F SHOULD know that S won’t have a problem with her bringing extra people along.
(This made-up scenario was really lame. But I hope the Hadith is clear inshaAllah.)