Hi, I’m software and database developer with more than 35 years experience. The past 20 years I worked (full-time, in-situ) for two international organizations; IATTC, in San Diego, CA, and the Food and Agriculture Organization (FAO) of the United Nations, in Victoria, Seychelles. I'm currently retired, doing some freelancing to mainly to stay busy and up-to-date.
I have around 25 years of experience designing/developing databases and database-centric applications, as well as administering networks and workgroups.
It seems to me that what you have is basically a network problem. If I understand well, you require shared access to some resources (spreadsheets, in this case), this can be easily solved creating a LAN (Local Area Network) with VPN (Virtual Private Network) access for devices outside the office (e.g. intelligent phones, home PCs, etc.). I can certainly advise you the equipment you require to buy and how to set this up.
If you think you may be interested in my services, please send me a message, this way I can provide a copy of my CV (for you to check experience and references) and we can further discuss the details of the project
Best regards,
Marco García