Different style of filling in x direction

I have the following curves:

linea = Line[{{0.1, 0}, {0.1, 50}}]; Show[
Plot[{2/Abs[a], 3/Abs[a], 4/Abs[a], 6/Abs[a]}, {a, 0, 1}, 
Mesh -> {{0.1, 1}}, MeshShading -> {Dashed, Automatic, Dotted}, 
MeshStyle -> None, Filling -> {1 -> Axis}, 
PlotStyle -> {Thickness[0.005]}, 
Ticks -> {{0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1}, 

Automatic}, AxesOrigin -> {0, 0}, 
Epilog -> {Directive[Black, DotDashed], PointSize[.015], linea}]]

I would like to plot filling option with two different styles: for 0 < a < 1 light grey, for a>1 grey. How can I obtain this option? Moreover, how can I grow up the size of dash in DotDashed style of linea? Thank you

Answer

colors = ColorData[1, "ColorList"][[{1, 1, 2, 3, 4}]];
linea = Line[{{0.1, 0}, {0.1, 50}}]; 
Plot[{ConditionalExpression[2/Abs[a], a <= .1], 
  ConditionalExpression[2/Abs[a], a >= .1], 3/Abs[a], 4/Abs[a], 6/Abs[a]}, {a, 0, 1}, 
 Mesh -> {{0.1, 1}}, MeshShading -> {Dashed, Automatic, Dotted}, MeshStyle -> None, 

 Filling -> {1 -> {Axis, LightGray}, 2 -> {Axis, LightBlue}}, 
 PlotStyle -> Thread[Directive[colors, Thickness[.005]]], 
 Ticks -> {{0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1},  Automatic}, 
 AxesOrigin -> {0, 0}, 
 Epilog -> {Directive[Black, Dashing[{0, Small, Large, Small}]], PointSize[.015], linea}]