Theoretically, yes but it is easier to do with TeX:
@example
-\def\foo{\hbox{\vrule width 15.0cm height 0.5pt depth 0.0pt}
+\def\foo@{\hbox@{\vrule width 15.0cm height 0.5pt depth 0.0pt@}
\nointerlineskip
-\vskip 5pt\nointerlineskip}
-\def\musicline{\vbox {
+\vskip 5pt\nointerlineskip@}
+\def\musicline@{\vbox @{
\foo\foo\foo\foo\foo
-}\par}
+@}\par@}
\musicline
\musicline