Online Trick

Lattice graphs can be quite tedious to learn. I don't use them too often and  when I need them I usually have to dig deep into the archives for details on the parameter details.
The here presented example may serve as a welcome template for the usage of panel functions, panel ordering, for drawing of lattice keys, etc.
You can download the example data HERE.

(Also, check this resource with examples by the lattice-author). 

library(lattice)
df <- read.csv("PATH/TO/Downloads/lattice_data.csv",
               header = T, sep = ";")
mypch <- rep(21, 3)
mycol <- c(rgb(0.2, 0.8, 0.9), rgb(0.8, 0.2, 0.9), rgb(0.9, 0.2, 0.2))

stripplot(mean ~ group1 | item_parc, groups = group2, data = df,
          type = c("a", "p"), strip = strip.custom(strip.names = c(F, T)),
          ylab = "Score-Mittelwert", layout = c(2, 4),
          scales = list(y = list(cex = 0.9),
                        x = list(cex = 1.1, labels = c("männl.", "weibl."),
                        tck = c(1, 0))),
          par.strip.text = list(cex = 0.9),
          panel = function(...) {
             panel.stripplot(..., col = mycol, pch = mypch, fill = mycol)
          },
          index.cond = list(c(7,8,5,6,3,4,1,2)),
          key = list(space = "bottom", text = list(c("Alter < 35 J.",
                                                     "Alter 35-50 J.",
                                                     "Alter > 50 J.")),
                     points = list(col = mycol, cex = 0.8, pch = mypch, fill = mycol),
                     rep = F))

library(lattice)

y1 <- rnorm(120,100,10)
y2 <- rnorm(120,10,1)

facs <- expand.grid(Sites=rep(c("Site I","Site II",
                       "Site III"),20),Treatment = c("A","B"))

trellis.par.set(clip = list(panel = "off",strip = "off"),
   layout.widths = list(right.padding = 10,
   left.padding = 8))

PanFun<-function(...){
   panel.dotplot(...)
     if(is.element(panel.number(),1:2))
       {at<-pretty(c(min(y1),max(y1)))
        panel.axis("right",at = at,outside = T,
        labels = F,half = F)}
     if(panel.number() == 3)
       {at<-pretty(c(min(y1),max(y1)))
        panel.axis("right",at = at,outside = T,
        labels = T,half = F)}
     if(panel.number() == 4)
       {at<-pretty(c(min(y2),max(y2)))
        panel.axis("left",at = at,outside = T,
        labels = T,half = F)}
     if(is.element(panel.number(),5:6))
       {at<-pretty(c(min(y2),max(y2)))
        panel.axis("left",at = at,outside = T,
        labels = F,half = F)}}

dotplot(y1+y2 ~ Treatment|Sites,
        outer = TRUE,data = facs,
        scales = list(
             x = list(rot = 0, tck=c(1,0)),
             y = list(draw=F,relation="free",
        limits = list(range(y1),range(y1),range(y1),
                    range(y2),range(y2),range(y2)))),
        ylab = list("response one (y1)", y = 0.75, x = -4),
        ylab.right = list("response two (y2)", y = 0.25, 
                          rot = 270, x = 4),
        xlab = c("Site 1", "Site 2","Site 3"),
        strip = FALSE, panel=PanFun)

R package citation:
Sarkar, Deepayan (2008) Lattice: Multivariate Data Visualization with
R. Springer, New York. ISBN 978-0-387-75968-5

See also the thread:
http://www.mail-archive.com/r-help@r-project.org/msg107565.html

..and examples from:
http://lmdvr.r-forge.r-project.org/figures/figures.html