I have made a simple model in Blender where I have 2 rows of columns (6 columns in each). I made a row using array modifier and then copy it to obtain second row. Then I exported it as .gltf file to ...

it seems that the behaviour of &MULT could be replicated/translated to the Array Modifier and back. The I/J/K_UPPER could then be three arrays in the different axis. Maybe this could be an interesting ...