Find and replace with exact string

I need to find an exact string (i.e. "Room 1,2,3,4") in a sheet and replace it with another exact string (i.e. "Room 1, Room 2, Room 3, Room 4") in the same sheet.

How do I denote an exact string?

The problem I am having is:
find "Room 1,2,3", replace with "Room 1, Room 2, Room 3" and find "Room 1,2" and replace with "Room 1, Room 2" in the same sheet is finding "Room 1,2" within "Room 1,2,3" and replacing it with "Room 1, Room 2,3".

How could I make a more general find and replace that deals with all of these possible combinations?
How do I denote an EXACT string in VBA?