Can multiple notes be parenthesized as a group?

[Patrick or Cynthia Karl]

Consider:

        \version "2.18.0"

        \relative b' {
                c2 \parenthesize d
                c2 \parenthesize {d4 e}
        }

The pdf output for the first measure is correct, a half-note c followed by a 
parenthesized half-note d.  However, the second bar shows no evidence of any 
parenthesizing at all, nor any error indication in the log.  Is there a way to 
do this?  

I realize I could parenthesize the two notes separately, but that is not what 
is in the score I am trying to engrave.