MarvinSketch has a rich collection of features related to abbreviated groups.
More information can be found on the Abbreviated (superatom) groups page of Drawing more complex structures section.
Predefined Abbreviated Groups
A number of predefined abbreviated groups are available in MarvinSketch.
The complete set is listed in the Insert > Groups. These groups are also available as shortcuts.
The rotation of the molecule might change the groups' writing order, thus retaining the chemically correct connectivity.
The complete list of predefined abbreviated groups can be find here.
User-Defined Abbreviated Groups
You can easily create new groups that you often use. Select the structure and give it a name (Superatom (abbreviation) in Structure > Groups > Create Group) and if needed, define an attachment point. Add the newly created abbreviation group to the user.abbrevgroup file.
S-groups as My Templates
User-defined groups are, by default, session-only. To retain an abbreviated group for future use, add it to My Templates. This will also make the group available in the Groups menu or as a shortcut.