can the pdf output page break be controlled manually?

I would like to control where to make a page break in my pdf file.
The following code renders three pages of output. But I would like to be
able to control the page breaks.

pdf(file="test.pdf", paper="a4")
      par(mfrow=c(2,2))
      hist(rnorm(100))
	hist(rnorm(100))
      hist(rnorm(100))
	plot.new()

	par(mfrow=c(1,1))
	hist(rnorm(100))
	hist(rnorm(100))
dev.off()

It would be much more convenient though, to enter a page break command
within the code instead of plot.new().

Is there a way to do this?

TIA, Mark