save plots to different jpeg files in a for loop in R

I would like to accomplish the following in R: I one same for loop, I would like to save different plots to different jpeg files. My problem is that i don't know exactly how to tell R "save this plot in this open jpeg file and this other plot in this different jpeg file".

I can currently do this using two for loops:

library(data.table)

set.seed(10)

data1 <- data.table(A = letters[3:5], B = letters[6:8], 
                    C = rnorm(20), D = rnorm (20) )

for( i in unique(data1$A )){

  data2 <- data1[A == i]

  jpeg(paste(i,'plot1.jpg',sep = ''))

  hist(data2$C)

  dev.off()

}

for( i in unique(data1$A )){

  data2 <- data1[A == i]

  jpeg(paste(i,'plot2.jpg',sep = ''))

  hist(data2$D)

  dev.off()

}

However, I would like combine these two loops in a single one (what follows is not an actual code, but the idea of what I would like to accomplish):

for( i in unique(data1$A )){

  data2 <- data1[A == i]

  a <- jpeg(paste(i,'plot2.jpg',sep = ''))
  b <- jpeg(paste(i,'plot2.jpg',sep = ''))

  hist(data2$D, PLOT in a)
  hist(data2$D, PLOT in b)

  dev.off(CLOSE a AND b)

}