title: Include 2nd variable labels on an existing Variable vs sample plot geom_jitter
body: <p>I have a <code>geom_jitter</code> plot showing Variables between 2 samples, I would like to include the Group-variable parameters on the left of the plot, setting a separation by lines like in the figure below. Thus, Variables are organised by Group.</p>
  
  <p>Here is a reproducible example:</p>
  
  <pre><code>data&lt;- tibble::tibble(
    Variable = c("A","B","C","D","E", "F"),
    Group = c("Asia","Asia","Europe","Europe","Africa","America"),
    sample1 = c(0.38,0.22,0.18,0.12,0.1,0),
    sample2 = c(0.23,0.2,0,0.12,0.11,0.15))
  
  
  library(reshape2)
  data2&lt;- melt(data,
          id.vars=c("Variable", "Group"),
          measure.vars=c("sample1", "sample2"),
          variable.name="Sample",
          value.name="value")
  
  data22[is.na(data22)] &lt;- 0
  library(ggplot2)
  ggplot(data2, aes(x = Sample, y = Variable, label=NA)) +
      geom_point(aes(size = value, colour = value)) + 
      geom_text(hjust = 1, size = 2) +
      # scale_size(range = c(1,3)) +
      theme_bw()+
    scale_color_gradient(low = "lightblue", high = "darkblue")
  </code></pre>
  
  <p>Here is the current output I have:
  <a href="https://i.stack.imgur.com/GU0HW.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/GU0HW.png" alt="Current output:"></a></p>
  
  <p>And this is the format I would like:
  <a href="https://i.stack.imgur.com/I0zSK.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/I0zSK.png" alt="enter image description here"></a></p>