How to label group of ticks?

I am plotting a matrix in 3D and what I did so far is this:

So, what I would like to do now is to add different labels to group of ticks, in this way:

Even only on the bottom axis is perfect.

The code that I am using is this one:

iF = Interpolation[Join@@MapIndexed[Composition[Reverse, List], *list*,{2}]];

plot3DmW = DiscretePlot3D[iF[i, j], {i, 1, Dimensions[*list*][[1]]}, {j, 1,
Dimensions[*list*][[2]]}, ExtentSize -> Full,FillingStyle -> Opacity[1],
ColorFunction -> "LightTemperatureMap",Axes -> True,Ticks -> {{{1, "-6,L"},
{2, "6,R"}, {3, "-7,L"}, {4, "7,R"}}, {{1,"-6,L"}, {2, "6,R"}, {3, "-7,L"},
{4,"7,R"}}, {0, 1}},AxesLabel -> {None, None, "Probability"},LabelStyle ->
Directive[Black, Bold, Medium],PlotLegends -> Automatic, ViewPoint -> {4, 10, 10}]


I hope you can help me and teach me more!

• Solved! The changes have been made only in the Ticks, so I leave here only that part that solve the problem: Ticks -> {{{1, "-6,L"}, {1.3, Style["\nB", Bold, 16]}, , {2, "6,R"}, {3, "-7,L"}, {3.25, Style["\nA", Bold, 16]}, {4, "7,R"}}, {{1, "-6,L"}, {2, "6,R"}, {3, "-7,L"}, {4, "7,R"}}, {0, 1}} Oct 18, 2017 at 10:35

Ticks -> {{{1, "-6,L"}, {1.3, Style["\nB", Bold, 16]}, , {2, "6,R"}, {3, "-7,L"}, {3.25, Style["\nA", Bold, 16]}, {4, "7,R"}}, {{1, "-6,L"}, {2, "6,R"}, {3, "-7,L"}, {4, "7,R"}}, {0, 1}}
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