After all of the cells are listed, they are organized into groups. Each group line consists simply of a list of cells in that group. The first cell listed is the "main schematics" of the group. If there is no such cell, the first field is empty. After that, the cells appear in alphabetical order.

Group lines are optional, because much of the group information can be derived from the cell names and cell group fields.

When multiple groups are declared, they appear sorted by the group name (which is derived from the cell names in it). The syntax is:

G<cell> | <cell> | ... | <cell>
<cell> | the name of the cells in the group. <cell> may consists only of proto name, because all cells with the same base name are put into the same group.

Examples:

`Gsam;2{sch}`

"sam;2{sch}" is the main schematic of the cell group consisting of all views and versions of cells with proto name "sam".

`G|high|higha`

Places all views and versions of cells with proto names "high" and "higha" in the same group (there is no main schematic).