Q&A: Could ActiveStock manage stock levels from a common source on more than one website?

Yes, this could be possible. If the websites are running on the same server then it should be fairly straightforward - all the sites would be able to directly access the uploaded stock file. Of course, they would also have to share the same off-line (i.e. Actinic) stock data source for uploading changes to the stock levels.

If the sites are on different servers then some more involved customistaion would be required so that one site acts as the master and the others issue http calls to the master site to read from and write to the stock file.