Sorry for the delay just checking on this! I believe that is a product gap to use data from two different projects in the same organization. While you can move boards between projects within the same organization using the “Move” feature, this does not actually transfer the underlying data. It only copies the board structure, and you would need to reconfigure the events and properties in the new project. This is explained in the Move Boards documentation.
If you absolutely need to combine data from multiple projects, the only option would be to export the data from one project and import it into another using Mixpanel’s APIs. I would recommend either creating the same board for each project and analyzing each that way or having a property to distinguish the data (like app name or device) and put them in a single project.
