Custom caesura command

[Matthew]

Not wanting to type a long \override command in every staff I want a caesura, I
tried defining a command to shorten things for me :) . This is what I've tried
so far:

caesura = {
  \override BreathingSign.text = \markup { \musicglyph 
#"scripts.caesura.straight" }
  \breathe
  \override BreathingSign.text = \markup { \musicglyph #"scripts.rcomma" }
}

As you might guess, it doesn't work. Specifically, the breathe mark that appears
is an rcomma, which also happens when I inline this. I guess this is because I
need another note to appear before the next override. It works if I remove the
rcomma override, though I'd like to "un-override" BreathingSign.text within the
command.

My question is, is there a way to accomplish this? Some way to make that command
there take the next note as a parameter? I realize I could come up with an
\uncaesura command, though I'd rather keep this to one command if possible. I
wouldn't be surprised if a proper Scheme function will be needed to this,
actually.