Duplicate Surface Meshes in different Gmsh files

Question

My objective is to get a conformal surface mesh between two geometries meshed independently in different files. By example, I can start with a simple cube in one .geo file and mesh this geometry.

The script for this test1.geo file is as follows:

        // points - Block 1
       L = 1; H =1; Fin = 1/5; e =1; // L = length, H = width, e = elevation (z axis), Fin = mesh-size  

    Point(1) = {0,0,0, Fin};
    Point(2) = {L/2,0,0, Fin};
    Point(3) = {L/2,H,0, Fin};
    Point(4) = {0,H,0, Fin};
    Point(5) = {0,0,e, Fin};
    Point(6) = {L/2,0,e, Fin};
    Point(7) = {L/2,H,e, Fin};
    Point(8) = {0,H,e, Fin};


Line(1) = {1,2};
Line(2) = {2,3};
Line(3) = {3,4};
Line(4) = {4,1};
Line(5) = {5,6};
Line(6) = {6,7};
Line(7) = {7,8};
Line(8) = {8,5};
Line(9) = {1,5};
Line(10) = {2,6};
Line(11) = {3,7};
Line(12) = {4,8};


// surfaces Block 1
Line Loop(1) = {-1,-2,-3,-4};
Plane Surface(1) = {1};
Line Loop(2) = {5,6,7,8};
Plane Surface(2) = {2};
Line Loop(3) = {1,10,-5,-9};
Plane Surface(3) = {3};
Line Loop(4) = {2,11,-6,-10};
Plane Surface(4) = {4};
Line Loop(5) = {3,12,-7,-11};
Plane Surface(5) = {5};
Line Loop(6) = {4,9,-8,-12};
Plane Surface(6) = {6};



// Volume Block 1
Surface Loop(1) = {4,1,3,2,5,6};
Volume(1) = {1};

For various reasons, I need to write explicitly define all the lines and surfaces.

A part of the surface 4 has a physical interface with the second .geo file. i.e.

test2.geo

L = 1; H= 1; e = 1; Fin = 1/50;


Point(13) = {L/2,0,0.1*e, Fin};
Point(14) = {0.9*L,0,0.1*e, Fin};
Point(15) = {0.9*L,H,0.1*e, Fin};
Point(16) = {L/2,H,0.1*e, Fin};
Point(17) = {L/2,0,0.9*e, Fin};
Point(18) = {0.9*L,0,0.9*e, Fin};
Point(19) = {0.9*L,H,0.9*e, Fin};
Point(20) = {L/2,H,0.9*e, Fin};

Line(13) = {13,14};
Line(14) = {14,15};
Line(15) = {15,16};
Line(16) = {16,13};
Line(17) = {17,18};
Line(18) = {18,19};
Line(19) = {19,20};
Line(20) = {20,17};
Line(21) = {13,17};
Line(22) = {14,18};
Line(23) = {15,19};
Line(24) = {16,20};    


Line Loop(13) = {-13,-14,-15,-16};
Plane Surface(13) = {13};
Line Loop(14) = {17,18,19,20};
Plane Surface(14) = {14};
Line Loop(15) = {13,22,-17,-21};
Plane Surface(15) = {15};
Line Loop(16) = {14,23,-18,-22};
Plane Surface(16) = {16};
Line Loop(17) = {15,24,-19,-23};
Plane Surface(17) = {17};
Line Loop(18) = {16,21,-20,-24};
Plane Surface(18) = {18};


// Volume Block 2
Surface Loop(13) = {16,13,15,14,17,18};
Volume(13) = {13};

I want a conformal mesh on the mating physical interface between the .geo files which is shown by the red arrow.

The previous posts I read had a complete surface mating so it was possible to duplicate the surface use the Geometry.CopyMeshingMethod = 1 option, however this is not the case that I have. any suggestions, comments could be helpful! Thanks a lot in advance,