The Community has you covered, @nbuckler.
In QuickBooks Online (QBO), you can use the location tracking feature to organize data from different locations. To start, let's enable this feature in the Account and Settings menu.
Next is to add a location and name it under the name of the 4 companies:
Here's the article that will provide more info about the process: Set up and use location tracking.
When finished, make sure to choose the appropriate location for each expense. This way, we can ensure that transactions such as expenses are linked to the correct company or location.
To view the transactions under each locations, you can run a report for each:
Please let me know if I can be of additional assistance or should you have any follow-up questions about tracking expenses for a different company. I’ll be here to help. Have a good one.