$Group function specifies depended item of the group.
It has two mandatory parameters: group number and column in the group. Both parameters must be greater than 0.
- It is strongly recommended to define the group before use. For example, if you want to unite columns #5, #6 and #8 to group,
you should define a group for column #5 and use $Group(...) calls for #6 and #8.
$Group(2,3) call refers to column #3 of the group #2.