Which cross-stores scenarios architecture better?

[fiberliber]

Question, about scenarios architecture

Is it possible situations, when scenarios from one store, could needs to use actions from another, or if this happens, then we should treat that as architectural problem, which means that stores should be united to one single store, or point on needs in architecture refactoring?

So, if this is normal situations, then we should implement something like dependency injection between stores, but if this is an antipatternm, than we should explaine limitations about rules of spliting Single Source of Truth (SST) on isolated stores, which sould be independent from each other