I have proposed that this is a duplicate of [this](http://mathematica.stackexchange.com/questions/34035/hatched-bars-and-bar-specific-background-in-barchart) question, but for clarity I will show how by adapting the answer given there.

 barHatched[gap_, h_, seg_][{{xmin_, xmax_}, {ymin_, ymax_}}, ___] := 
 Module[{width, line, yt, yb, lend}, {yb, yt} = Sort[{ymin, ymax}];
 width = xmax - xmin;
 line = Table[{{xmin, i}, {xmax, i + width}}, {i, yb, yt - width, 
 h/seg}];
 lend = line[[-1, 1, 2]];
 line = {
 Line[line], 
 Line[Table[{{xmin + i, yb}, {xmax, yb + width - i}}, {i, h/seg, 
 width, h/seg}]], 
 Line[Table[{{xmin, lend + i}, {xmax - (lend + width - yt) - i, 
 yt}}, {i, h/seg, width + h/seg, h/seg}]]
 };
 {{Opacity[.2], EdgeForm[], 
 Rectangle[{xmin, ymin}, {xmax + gap, ymax}]},
 {CapForm["Butt"], line}, {FaceForm[], 
 Rectangle[{xmin, ymin}, {xmax, ymax}]}}
 ]
 
 barSolid[{{xmin_, xmax_}, {ymin_, ymax_}}, ___] := Rectangle[{xmin, ymin}, {xmax, ymax}]
 
mixedBar[args : {{xmin_, xmax_}, {ymin_, ymax_}}, ___] := 
 If[xmax < 3, barHatched[0, 5, 35][args], barSolid[args]]

BarChart[
 Transpose[{
 {2, -1, 1.5, -3, 3, 2.5},
 {2, -1, 1.5, -3, 3, 2.5}
 }],
 ChartElementFunction -> {
 mixedBar,
 barSolid
 }
 ]

![Mathematica graphics](https://i.sstatic.net/GMOIU.png)

The idea is to build custom `CharElementFunction`s for the bar appearances. To have variation with a set we need to make a `ChartElementFunction` which depends on the position of the bar.