The following is an example of one method for accessing the entities contained in a group. This example assumes a group named G1 exists in the current drawing.
(setq objdict (namedobjdict))
(setq grpdict (dictsearch objdict "ACAD_GROUP"))
This sets the grpdict variable to the entity definition list of the ACAD_GROUP dictionary and returns the following:
((-1 . <Entity name: 8dc10468>) (0 . "DICTIONARY") (5 . "D")
(102 . "{ACAD_REACTORS") (330 . <Entity name: 8dc10460>)
(102 . "}") (100 . "AcDbDictionary") (3 . "G1")
(350 . <Entity name: 8dc41240>))
The following code sets the variable group1 to the entity definition list of the G1 group:
(setq group1 (dictsearch (cdar grpdict) "G1"))
((-1 . <Entity name: 8dc10518>) (0 . "GROUP") (5 . "23")
(102 . "{ACAD_REACTORS") (330 . <Entity name: 8dc10468>)
(102 . "}") (100 . "AcDbGroup") (300 . "line and circle") (70 . 0) (71 . 1)
(340 . <Entity name: 8dc10510>)(340 . <Entity name: 8dc10550>) )
The 340 group codes are the entities that belong to the group.