Well yes it would be cheaper, but been advised if we have separate connections then if say one of the flats download / up-loaded something illegal and the police were involved then it would be easy to prove who was using that connection on a certain date .
You can get around that:
- Take a business service from someone like Cerberus (£60+VAT pm for 900/110)
- Get a /29 of public IP addresses (8 addresses). May cost a few quid extra.
- Configure the router with a different private subnet for each apartment
- Configure it to NAT each subnet to a different public address
- Configure it to block apartment-to-apartment traffic
A router like Mikrotik RB4011, with 10 ethernet ports which can be separately routed, will work very nicely for this (1 for ONT and 8 for the apartments)
You need to understand a little about IP networking when setting it up, but once done, you can forget it.