Remove unnecessary vertices after polyedit merge

Hello,
I have a simple beginner question about PolyModeling tool.

I have a large cube grid that I split up using Edge Loops. Then I want to merge the following poly groups that I have selected:

After I merge them I end up with superflous vertices like highlighted here

How do I remove these vertices? I tried selecting the merged polygroup and “Simplify By Groups” and “Retriangulate” but the vertices remain

i normally use TriSel in TriModel, mark it with brush and press Del, that will delete , then just Accept changes