As far as i know, that’s not really possible. it would basically mean that you can write queries that update the casedb.
i’m personally using this functionality to do a number of things such as recording attendance to activities or to enroll beneficiaries into activities. both beneficiaries and activities are case types that i also use elsewhere in the project. having the ability to show beneficiary cases on an activity update form is how we record enrollments into them for example.
basically, if you can correlate cases together in a way other than parent-child, you can then leverage that foreign key assignment (in database terms) to produce all kinds of analysis. therefor, in a way, displaying an update or an addition to the information through leveraging your data downloads.