[otrs] Default groups for customers authorized thru LDAP

Good day. We are using otrs to resolve incidents from external clients, and we are using Customer Groups feature. Now we need to use OTRS for internal company's purpose, so every employee will auth using LDAP. But i got problems with groups - i can't find a way to setup groups for customers authorized using LDAP. Without group customers (company's employers) can't post incidents to internal queues. Is there way to resolve this problem? Best regards.