Voip telephone system

Ive been given the dawnting task of coming up with a voip telephone system for my company based in Portugal. We have many websites for different clients with portuguese telephone numbers, although most of our clients customers are calling from the UK.
We need a phone service that allows us to answer each call while displaying the name of the particular website the customer is calling.
This voip system should accept incoming & make outgoing calls for different DID and also have crm along with all the extras, music on hold, mailbox, voicemail etc.
We also need to keep the portuguese numbers as the customers believe they are calling each of our clients direct.
Any help or advice on how to get started with this would be greatly received.

Bom Dia grooming7 and welcome to Voipuser.

The facilities you describe could all be set up within Asterisk so I suggest you take a look through some basic info on the application just to get a feel for what is possible and the system requirements.

Asterisk can be set up to work alongside Sugar CRM which is an outstanding programme (OS Version available free and well supported via an active forum).

Since most of your calling seems to be to and from the UK you would probably be better (and find it cheaper) with a UK Voip provider - there are plenty of good ones to choose from.

There is a lot to set up and I think you would be well advised to employ a systems engineer with some experience. He/She will also be able to make some suggestions on the hardware requirements and quote for the different options.