property Items.CellRadioGroup([Item as Variant], [ColIndex as Variant]) as Long

Retrieves or sets a value indicating which radio group a cell is contained in.

TypeDescription
Item as Variant A long expression that indicates the item's handle.
ColIndex as Variant A long expression that indicates the cell's handle or the column's index, a string expression that indicates the column's caption or the column's key.
Long A long expression that identifies the cell's radio group.

Use the CellRadioGroup property to add or remove a radio button from a group. In a radio group only one radio button can be checked. A radio cell cannot be contained by two different radio groups. Use the CellHasRadioButton property to add a radio button to a cell. When the cell's state is changed the control fires the ViewItemStateStartChanging(exCheckItem) / ViewItemStateEndChanging(exCheckItem) event. The CellState property specifies the cell's state. By default, when a cell of radio type is created  the radio cell is not grouped to any of existent radio groups