There are 8 offices plus a front desk (all in the same story). In each
office the person must be able to receive on its own number. Then, we
should be able to make at least 2 calls contemporary, either from 2
different offices, or one office and front desk. Also, when a person
calls, she should be able to dial the party extension before
transferring the call to the front desk.
In summary: min 2 tel # to call out at the same time, 8 to 10
different numbers simply to receive. A fax line at the front desk
would be a plus.
In addition, the offices (at least

and front desk should be able to
intercom between each other. The front desk must be able to transfer
calls to the office; the office should be able to re-transfer the call
to the front desk.