Just in case you are in QLD (the use of the term ‘body corporate’ may hint at SJ1965 being from QLD) …… the intercom may not be the responsibility of the body corporate.
Utility infrastructure is not necessary a “common property” matter for which the Body Corporate is liable. If the infrastructure is on common property, but solely supplies an individual lot – the owner of the lot is liable. Pipes, wires etc are included as utility infrastructure.
A definition of utility infrastructure is found here: https://www.qld.gov.au/law/housing-and-neighbours/body-corporate/maintenance/utility