When should a user create upstream, downstream. We know if you go down, you create downstream, however is there a `must` there, for instance prevent us saying all links must be created upstream? Can we check it with rules without customization?

How other people are doing to fix it, how they define the rlationships in TRY for instance, is it always upstream or there are downstream ones as well?

please suggest any example related to this or how to tackle it?