Get a Website Built

We are looking for website/online community site development. We are a construction company managing multiple projects. For each project that we manage, we would like have a restricted online community to individuals impacted by the project (unit owners). For this community, we would like to be able to easily deploy for new communities for new projects. Desired Functionality: 1) Ability for community admins to easily make posts to a homepage, which would include project status updates and pictures. 2)Ability for members to self register for the community. Self registration would ideally be restricted so individuals with a code etc. that is given to them by us would only be allowed to register. 3) Ability send mass emails with links to individuals to register. 4) Ability to send mass communication/broadcasts via email and/or text. This functionality should be able to restrict the communication based on the aspect(s) of the user profile (for example, all individuals that are in building 12). 5) User profiles should have ability to include required fields when individuals sign up (building and/or unit number). This should have the flexibility to be restricted based on a sub list when the community is established for building numbers. Unit numbers could be a text entry field. We have not identified a platform that would be the best to implement this functionality. Note, we currently utilize Salesforce and therefore are willing to consider Salesforce Communities.