Colaborative Family-tree (genealogy) website

I need to create a collaborative genealogy website for the italian community in Brazil. The idea is that my website visitors can input their data as in ordinary genealogy services out there: Name, Surname when born Name, Surname when after marriage or name change Date of birth, death, marriage Location now, location born personal photo additional photos (family photos) etc,.. Each visitor can add and edit their relatives and even edit other families The family tree is not meant to be for one family only but more a project where all users share the common profile, which is some kind of Italian ancestry. Website admin should aso be able to add people and families and also import GEDCOM files. I found some interesting services out there like [login to view URL] , [login to view URL], [login to view URL] and I would like to have similar pedigree visualization feature. I am not sure if those services provide API so I can embed the big family tree project inside my website. The genealogy website should be open and collaborative. Everybody shoul be able to make searches by all items listed above. Only for providing data login should be required. If a user edits data from other user maybe some validation could work like for example ask person who provided data before if he agreed with the modification. I accept more ideas and want the website to be as clean and simple, but functional possible. Third party services may be used as long it can be shown as being my website or at least inside my website.