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We are a business consulting firm

For years, our work was saved in a harddisk and we would access it over the LAN. Now we have two offices. So the issues are this

1. Work happens in both offices and needs to be accessible to both sets of people
2. There is a library team which collates all the work and tags them appropriately
3. Data Access privileges for project teams, guests, partners, etc have to be provided

Assume networking/bandwidth is not an issue, what is the best/cheapest/maintenance friendly architecture we can go for?

Users are primarily all non-techies but familiar with browsers, etc.