Mixing Grounds from different panels.

We have numerous light poles (208V) installed thoughout a parking lot. Some of the poles have a receptical (120V) installed. The circuits are run from seperate panels located in an electricl room and changeover from EMT to PVC upon leaving the building. My question is this: is it permissible to attach all the grounds together (both the light and receptical) inside the pole or should they be kept seperate and routed to respected panels?