Users wanted a way to view kinda-related data for records in different tables. The solutions was to take those and make them child tables of the rows in the parent table. It will probably be easiest to explain with an example.
Imagine you have a table of restaurants with an extreme amount of data for each record (talking horizontal scrolling here). This grid also includes several (anywhere between 1 and 15) columns with + buttons, though I'm planning on collapsing them into a single button with a popup to select which grid you wanted. These buttons have tooltips indicating the various subgrids you can see (for example, locations or menu items). When clicked, a row beneath the clicked cell expands with a new grid containing info relating to the button clicked. Multiple subgrids can be expanded at the same time, including for the same parent row.
Personally, I don't care for the design. The problem is that the users still want to be able to see all this information on the same screen for multiple records, so links to different pages and popup windows are not an option.
What are some alternatives to this table-in-a-table layout I could use?