Earth belongs to solar system’. > The solar system is the owner of earth . Belongs to > show ownsership.
Earth is part of our sloar system >better
This land / bag / computer/ money belongs to me ( I am the owner of these things ) .
Synonyms for 'belong to'? This is his land / his computer etc
‘The issue of Syria belongs to international issue, not domestic issue’. X
The issues of Syria is an international issue , not a domestic issue.
An issue cannot be a owner . Just like you cannot say" This belongs to international matters"
The nearest you can say is "This issus should belong to The United Nation , so that they can take actions ".