I have a matrix containing the nodes and a matrix containing the triangular faces of two 3D geometries as shown below:

Is there any way to split the two geometries? Then extract only nodes/triangles of the geometry in the yellow box?

file_im = importdata("f_mm.mat");

nodes_e = file_im.nodes_e;

faces_e = file_im.faces_e;

g_P_sez = file_im.g_P_sez;

trimesh(faces_e(:,:),nodes_e(:,1),nodes_e(:,2),nodes_e(:,3),'EdgeColor','k','Linewidth',0.1,'Facecolor',[255 0 0]/255,'FaceAlpha',1)

plot3(g_P_sez(:,1),g_P_sez(:,2),g_P_sez(:,3),'k.','Markersize',15)