Edward and Barbara: Thanks for your time. I appreciate your help
I have File_a (master), File_b(detail), File_d and File_e.

Grid1 ChildOrder: x_id
LinkMaster: File_a
RecordSource: File_b

Column 4 Of Grid1
grcDim ControlSource: File_b.field_xx
CurrentControl: cboDim

cboDim ControlSource: File_b.field_xx
RowSource: select ...... From file_e..... into cursor cDim where rol_id = Grid1.Col1.text1.value