I would use LevelScheme for this.
Quiet@Needs["LevelScheme`LevelScheme`"]
Figure[{
SetOptions[SchemeObject, FontFamily -> "Helvetica LT Std",
FontSize -> 08],
Multipanel[{4, 3},
Margin -> 50,
XPlotRanges -> {0, 25},
YPlotRanges -> {0, 100},
XFrameLabels -> None, BufferB -> 5,
YFrameLabels -> None, BufferL -> 7,
XFrameTicks -> Automatic,
YFrameTicks -> Automatic,
YGapSizes -> .05, XGapSizes -> .05,
YPanelSizes -> 1,
XPanelSizes -> 1,
First -> "A",
Order -> Horizontal
],
FigurePanel[{1, 1}],
RawGraphics@ListPlot[Prime[Range[25]], Frame -> True],
FigurePanel[{1, 2}],
RawGraphics@ListPlot[Prime[Range[25]], Frame -> True],
FigurePanel[{1, 3}],
RawGraphics@ListPlot[Prime[Range[25]], Frame -> True],
FigurePanel[{2, 1}],
RawGraphics@ListPlot[Prime[Range[25]], Frame -> True],
(*FigurePanel[{2, 2}],*)
FigurePanel[{2, 3}],
RawGraphics@ListPlot[Prime[Range[25]], Frame -> True],
FigurePanel[{3, 1}],
RawGraphics@ListPlot[Prime[Range[25]], Frame -> True],
FigurePanel[{3, 2}],
RawGraphics@ListPlot[Prime[Range[25]], Frame -> True],
(*FigurePanel[{3, 3}],*)
FigurePanel[{4, 1}],
RawGraphics@ListPlot[Prime[Range[25]], Frame -> True],
FigurePanel[{4, 2}],
RawGraphics@ListPlot[Prime[Range[25]], Frame -> True],
FigurePanel[{4, 3}],
RawGraphics@ListPlot[Prime[Range[25]], Frame -> True]
},
ImageSize -> 500
]
An extensive manual & examples allows lots of fine tuning of the resulting plot

Null
instead ofblank
. $\endgroup$ – Henrik Schumacher May 18 '18 at 6:58