You can split multiple polygon faces in one operation using the Cut Faces Tool (Edit Mesh > Cut Faces Tool). The tool can also split polygons across multiple polygon meshes in one operation.

Using the Cut Faces Tool you can:
To cut faces along a line you draw
.
When the Delete cut faces option is on, a dotted line shows which side will be deleted.
Once you have cut the faces, you can select the polyCut node and click the Show Manipulator tool to further modify your work.
To cut faces along a defined plane
.
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