I have an existing Excel application which meets you requirement and could be readily adapted to create your add-in.
The application is a Resource Planner which interfaces to a shared Access database which stores all the planning and time recording data. I developed an interface using class modules which allow ranges on the Excel worksheet to be defined as data cells which read and write to the shared data tables. From a users point of view it is like a shared workbook – breaking the single user limitation of Excel workbooks. However because it has been developed using class modules and named ranges, the code is totally generic and can be applied to any worksheet with just a few lines of code.
I have over 20 years experience developing applications in Access, with particular skills in integration with Excel, Word and Outlook. I have also written standalone add-ins in each of these platforms.
I have clients in countries all over the world, including the USA, Canada, Europe and Australia, . We interact via email, telephone and TeamViewer. . My morning is your afternoon but I work flexible hours if we need to talk.
Please call me without obligation on +44 292 125 8848 to discuss your project further. I am generally available from 08:00 to 18:00 BST / 15:00 to 01:00 SGT
Or message me with more detail or if you have questions.
Kind regards
Neil Sargent
Please note: I have bid a guide price which may change once a detailed specification has been agreed.