I have been to places where they have precisely what you describe as an entry system, not sure where you would get one from though, a company selling home security might be a good start.
my video entry is knackered at the moment and I've had a quote of £480 ro replace it, but that does include door release from Dorcom 0800 068 5447 or 01273 202851. But you can get cheaper units from wholesalers for about £250 and get fitted by an electrician, they won't touch them.
But if their engineers are like their sales guy forget it. Been waiting for over a week for written quote so I can submit to managing agent despite 3 phone calls.