Steve Jones didn’t keep ’em separated:
I had a question on multiple backups in a file and had to check my syntax. This post shows how to see which backups are in a file.
Note: Don’t do this. Put backups in separate files.
Still, if you didn’t follow Steve’s good advice here (or you have an edge case situation where you, for some reason, need to store multiple backups in the same file), there’s a way to check what’s in a file.