gridlines and more then 1 building

I have a drawing (planview)

gridlines for the right building (IL-*) are showing correct, but also the grid lines from an other accompanying building (DC-*) are showing up in the drawing

In the 3D file, only the correct grid for the building is selected (IL)

how to hide the grid for the other building (DC- )

I have updated the floornames to unique ones (the where the same name in different buildings) with no result

OBD  u6 &7