I am installing a partner ACS R6.0 system in a small motel (16)rooms. The system will have 4 outside lines and 20 extensions total. The single line sets are programmed for automatice line selection with intercom (dial 9 for outside dialtone) as the first choice. Do I need to assign both intercoms as the first selections in ALS or just intercom 1? Any advantages disadvantages using both? Thanks