Cross references - how to reference both ways?

I want to include hierarchical information in a termbase. E.g. toe nail is part of toe, toe is part of foot, heel is part of foot, foot is part of leg etc. So I have parent-child relationships. Of course, if A is the child of B, then B is the parent of A. Is there a convenient way to do that in MultiTerm? All I can see at the moment is to manually enter the link to B in A, then select entry B and manually enter the link to A in B... This could be automatic, could it not?