I don't think the question is so terribly bad. But the data representation makes the problem awkward to understand and solve. First I put your data in another form, {m, R, E}:
$m = Range[0, 3]; (* domain for m *)
$R = Range[50, 250, 50]; (* domain for R *)
L[m_, R_] := If[Head[#] === Symbol, {}, #] &@
Symbol["Lm" <> ToString[m] <> "R" <> ToString[R]];
energyData = Flatten[Table[Thread[{m, R, L[m, R]}], {m, $m}, {R, $R}], 2]
If you don't understand the code, don't worry (see addendum). Look at the output below. This is how you might represent your data better; enter it this way, if you can.
{{0, 50, 0.186825}, {0, 100, 0.121567}, {0, 100, 0.2715},
{0, 150, 0.0992422}, {0, 150, 0.195237}, {0, 200, 0.0888446},
{0, 200, 0.153953}, {0, 200, 0.24331}, {0, 250, 0.083121},
{0, 250, 0.130411}, {0, 250, 0.197507}, {0, 250, 0.274236},
{1, 100, 0.184144}, {1, 150, 0.136613}, {1, 150, 0.251408},
{1, 200, 0.113951}, {1, 200, 0.19403}, {1, 250, 0.101237},
{1, 250, 0.160137}, {1, 250, 0.234342}}
I assumed you wanted to plot the levels for each value of R separately. So I defined a function to select out the data with a given R value:
en[R_] := Cases[energyData, x : {_, R, _} :> Drop[x, {2}]]
For example:
en[250]
{0, 0.083121}, {0, 0.130411}, {0, 0.197507}, {0, 0.274236},
{1, 0.101237}, {1, 0.160137}, {1, 0.234342}}
Then you can use ListPlot with a special PlotMarker that is a red line graphic:
With[{R = 250},
ListPlot[en[R],
PlotMarkers -> {Graphics[{Red, Thick, Line[{{-1/2, 0}, {1/2, 0}}]}], 0.5},
PlotRange -> {{-0.5, 3.5}, {0, Automatic}},
Frame -> {{True, False}, {True, False}}, Axes -> False,
FrameTicks -> {{Automatic, None}, {$m, None}}]]

Edit: Incorporating @rcollyer's solution
I misunderstood the question, and this seems to get at the original intention to combine the plots for each value of R:
ListPlot[GatherBy[energyData, #[[2]] &][[All, All, {1, 3}]],
PlotMarkers -> {Graphics[{Thick, Line[{{-1/2, 0}, {1/2, 0}}]}], 0.5},
PlotRange -> {{-0.5, 3.5}, {0, Automatic}},
Frame -> {{True, False}, {True, False}}, Axes -> False,
FrameTicks -> {{Automatic, None}, {$m, None}}]

Addendum: The strange function L above
The original energy levels were stored in variables with names that seemed to be in the form:
LmxRyyy = {E1, E2,...}
where x was the corresponding value of m (0, 1, etc.) and and yyy was the corresponding value of R (50, 100, etc.). The idea was to convert these into a single list of elements of the form {m, R, E}, one for each energy level with its corresponding m and R. To do this, I wanted a function L that, for m = x and R = yyy, would return LmxRyyy. At first glance this seems to work:
L[m_, R_] := Symbol["Lm" <> ToString[m] <> "R" <> ToString[R]];
For instance L[0, 150] returns Symbol["Lm0R150"] which is the same as the variable Lm0R150.
So far, so good. If Lm0R150 is defined, then evaluation of L[0, 150] will be the list of energies. The difficulty arise when the variable is undefined. L[1,50] returns the symbol Lm1R50, which is undefined. I wanted the default to be an empty list, so I added a test in the form of a pure function:
L[m_, R_] := If[Head[#] === Symbol, {}, #] &@
Symbol["Lm" <> ToString[m] <> "R" <> ToString[R]];
If the Head of the evaluated Symbol["Lm" <> ToString[m] <> "R" <> ToString[R]] is still Symbol, then the corresponding variable is undefined and {} is returned; otherwise the variable is return. (In the pure function If[...]&, the # is replaced by the Symbol[...] expression. f@expr is the prefix form of f[expr].)
To understand how L is used to make energyData, one should probably start by evaluating
Thread[{x, yyy, {1, 2, 3}}]
(* -> {{x, yyy, 1}, {x, yyy, 2}, {x, yyy, 3}} *)
It creates a list of the form {m, R, E}. These are then collected in a table, which is flattened.
energyData = Flatten[Table[Thread[{m, R, L[m, R]}], {m, $m}, {R, $R}], 2]
$m and $R were defined to contained all the apparent values of m and R, so that the table would include all possible combinations, and energyData would contain all data.
Now
en[R_] := Cases[energyData, x : {_, R, _} :> Drop[x, {2}]]
finds all cases of triples in energyData whose second element is R and drops the second element. The result is a list of elements of the form {m, E}, exactly those for the given value of R.
Note: I changed LmR100={0.157144} in the original question to Lm1R100={0.157144}, which I took to be a typo.
R? What do I have to do to get the 3 numbers you plotted form=0from the 12 numbers you gave form=0? – acl Mar 6 at 21:30