Q:

Plot challenge: two bar charts next to next with one indicator line

Simple task:
I would like to place two bar charts in a row and have an indicator horizontal line going above the two bar charts.
What I did:
bar1 = BarChart[{100, 75, 100}, ChartLayout -> "Stacked", 
   ChartStyle -> {Blue, Black, Blue}, Frame -> False, Axes -> False, 
   PlotLabel -> "bar1"];
bar2 = BarChart[{100, 38, 15, 38, 85}, ChartLayout -> "Stacked", 
   ChartStyle -> {Blue, Black, White, Black, Blue}, Frame -> False, 
   Axes -> False, PlotLabel -> "bar2"];
indicator = 
  Plot[-65 + 100, {x, 0, 4}, PlotStyle -> Red, 
   PlotLegends -> ToString[65]];

To combine the plots, I tried:
Show[Row[bar1, bar2], indicator]

but the result:

HELP !
The colors need to be the same.
This is how it should look like in the end:

A:

Use Epilog and GraphicsRow. Something like
GraphicsRow[{bar1, bar2},
  Spacings -> -20,
  Epilog -> {Red, Thickness[0.02], Line[{{0, -180}, {750, -180}}]}
 ]

and you can change the coordinates {{0, -180}, {750, -180}} of the Line by trial and error to get what you want (that's how I usually do it). The result is

