The ornamental design for a crosssupportgridmember for a suspendedceiling, as shown and described.
FIG. 1 is a perspective view of a cross support grid member for a suspended ceiling and showing my new design;
FIG. 2 is an end view thereof;
FIG. 3 is the opposite end view thereof;
FIG. 4 is a side view thereof, the opposite side view being a mirror image;
FIG. 5 is a top view thereof; and,
FIG. 6 is a bottom view thereof.
FIGS. 1, 4, 5, and 6 are shown with a symbolic break in the length of the cross support grid member for a suspended ceiling. Any portion of the article between the break lines forms no part of the claimed design.