Hi @Mike5 - You can use Tags, but you can also just as well create your own custom column in the Transactions sheet and classify each entity/business/investment in that custom column. I do this with real estate for example.
A benefit to the Tags column is that it is already supported in several community templates and Tiller solutions. Adding a custom column would likely require customized reports.
There are a lot of community discussions on P&L that you can look into. I’ve created some customized P&Ls that can be aggregated on any column including Tags. So for my own case, I can run the P&L by months/time for a single entity, or I can run the P&L by an aggregator, viewing multiple investments side by side. This becomes useful when one entity owns multiple investments. I don’t generate K1s but I do use those solutions to create Income statements used by a CPA at tax time.
Note that AutoCat can also run against a custom column, so there really are lots of ways to customize the set-up based on your individual situation.