If you don't want to have distinct definitions of groups and departments, you can import from departments. Use the button :
Importing groups from departments option in Configuration - Groups - Employees in Astrow Web
This will import all departments with employees linked. If you want to import all departments, not only those with employees linked, check the option Import from all departments.
Importing groups from departments in Astrow Web
All departments will be imported in groups.
Groups successfully imported from departments option in Astrow Web
Click Cancel to exit.
Please note that the validation is made by name, so if the name of the department is the same as the name of an existing group, the import will not be possible for that department.