\version "2.22.2"

one = \relative c' {
	\time 4/4
	R1
	\time 2/4
	\slashedGrace s8
	e8 r4.
	e8 r4.
	e4 r4
	e8 r4.
}

two = \relative c' {
	\time 4/4
	R1
	\time 2/4
	\slashedGrace s8
	%c4 r4
	r2
	c8 r4.
	c4 r4
	c8 r4.
}

reference = \relative c' {
	\time 4/4
	c1
	\time 2/4
	\slashedGrace g8
	c2
	R2
	R2
	R2
}

\score {
	<<
		\new Staff \one
		\new Staff \two
		\new Staff \partCombine \one \two
		\new Staff \reference
	>>
}