Best proof is that people call by themselves so they can hear it unfiltered.
"I want to sent flowers to Laxmi Palaypu Prasad aka Laxmi Prasad aka Laxmi Prasad Palaypu. Not sure if I am calling the right hospital. Don't need to know his room number, just need to know if I am sending it to right hospital. I am sure you could forward them ro right room number."
If they tell you no patient here by that name that should tell you enough.
You can do the same procedure at all three locations or simply call main switchboard.