How to apply \staccato to a single note in a chord?

[Ian Mackinnon]

I'm trying to represent a harp technique where two
adjacent notes are struck at the same time and the
lower of the two is immediately dampened.

I tried to create a chord with only the first (lower)
note marked as staccato, but the output showed
the staccato dot over the second, higher note
(indicating, I assume, that both should be played
staccato):

<bes \staccato c>  % dot shows over c.

Is there any way to show a staccato dot just over
the B flat while still having the C share the 
same stem?