How can I stack multiple ternary plots on top of each other in 3D?

Question

I have data to make multiple ternary plots, each having 3 points on it.

Is it possible to stack those ternary plots in 3D on top of each other? Then, is it possible to connect the points of the same color in each ternary plot with each other in 3D to see how, for example, the blue point evolves as you move in 3D.

Here is an example to make 2 ternary plots.

vec1 = {{{0.3, 0.4, 0.3}}, {{0.6, 0.3, 0.1}}, {{0.25, 0.25, 0.5}}}; 
vec2 = {{{0.25, 0.3, 0.45}}, {{0.5, 0.15, 0.35}}, {{0.2, 0.2, 0.6}}}; 
TernaryListPlot[{vec1[[1]], vec1[[2]], vec1[[3]]}, PlotStyle -> {Blue, Red, Magenta}, FrameLabel -> {"A", "B", "C"}, PlotStyle -> PointSize[0.04]]
TernaryListPlot[{vec2[[1]], vec2[[2]], vec2[[3]]}, PlotStyle -> {Blue, Red, Magenta}, FrameLabel -> {"A", "B", "C"}, PlotStyle -> PointSize[0.04]]

Can I stack these two and connect vec1[[1]] to vec2[[1]], vec1[[2]] to vec2[[2]] etc using a line?

Answer 1

Maybe this result?

Edit

Clear["Global`*"];
ternary[{p1_, p2_, p3_}] := {p1 + 1/2 p2, Sqrt[3]/2 p2};

vec1 = {{{0.3, 0.4, 0.3}}, {{0.6, 0.3, 0.1}}, {{0.25, 0.25, 0.5}}};
vec2 = {{{0.25, 0.3, 0.45}}, {{0.5, 0.15, 0.35}}, {{0.2, 0.2, 0.6}}};

pts1 = PadRight[#, 3] & /@ ternary /@ Flatten[vec1, 1];
pts2 = PadRight[#, 3, 1] & /@ ternary /@ Flatten[vec2, 1];
plane1 = 
  Polygon[PadRight[#, 3] & /@ 
    ternary /@ {{1, 0, 0}, {0, 1, 0}, {0, 0, 1}}];
plane2 = 
  Polygon[PadRight[#, 3, 1] & /@ 
    ternary /@ {{1, 0, 0}, {0, 1, 0}, {0, 0, 1}}];

Graphics3D[{{Opacity[.2], plane1, 
   plane2}, {MapThread[{#3, AbsolutePointSize[8], Point[#1], 
      Point[#2], Arrow[{#1, #2}]} &, {pts1, 
     pts2, {Blue, Red, Magenta}}]}}, BoxRatios -> Automatic, 
 Boxed -> False, Axes -> True, ViewProjection -> "Orthographic"]

Original

Clear["Global`*"];
vec1 = {{{0.3, 0.4, 0.3}}, {{0.6, 0.3, 0.1}}, {{0.25, 0.25, 0.5}}};
vec2 = {{{0.25, 0.3, 0.45}}, {{0.5, 0.15, 0.35}}, {{0.2, 0.2, 0.6}}};
plane = ContourPlot3D[x + y + z == 1, {x, 0, 1}, {y, 0, 1}, {z, 0, 1},
    Mesh -> None, ContourStyle -> {White, Opacity[0.8]}];
points1 = ListPointPlot3D[vec1, PlotStyle -> {Blue, Red, Magenta}];
points2 = ListPointPlot3D[vec2, PlotStyle -> {Blue, Red, Magenta}];
arrows = 
  Graphics3D[Arrow /@ Thread@{Flatten[vec1, 1], Flatten[vec2, 1]}];
Show[plane, points1, points2, arrows, PlotRange -> All, 
 BoxRatios -> Automatic, Boxed -> False, Axes -> False]

Answer 2

Pre-process input data to add z-coordinates and re-group:

zlevels = {1, 5};

vecs = Transpose @ MapApply[Map[Append[#]] @ Apply[Join][#2]&][
   Transpose @ {zlevels, {vec1, vec2}}]

 {{{0.3, 0.4, 0.3, 1}, {0.25, 0.3, 0.45, 5}},  
  {{0.6, 0.3, 0.1, 1}, {0.5, 0.15, 0.35, 5}},  
  {{0.25, 0.25, 0.5, 1}, {0.2, 0.2, 0.6, 5}}}

Use vecs with Charting`TernaryListPlot3D:

Charting`TernaryListPlot3D[vecs,
 "PlotBaseStyle" -> Directive[AbsolutePointSize[9]],
 PlotRange -> {-3, 9}, FaceGrids -> None, 
 PlotStyle -> Directive[FaceForm[], EdgeForm[]]]

Post-process to add arrows:

ReplaceAll[Point[x_] :> {Point[x], Arrowheads[Large], Arrow[x]}] @ %

If needed, add ternary clip-planes at desired z-levels:

Show[%,
 MapThread[
   Charting`TernaryListPlot3D[{{0, 0, 0, #}, {0, 0, 1, #}, {0, 1,  0, #}}, 
     "PlotBaseStyle" -> Directive[AbsolutePointSize[0]], 
     Ticks -> None, 
     PlotStyle -> Directive[FaceForm[Directive[Opacity[.1], #2]], 
       EdgeForm[]]] &][{zlevels, {Red, Green}}], 
 BoxRatios -> 1]