How to explain such a relationship/association (preferably not in the human context) :
Approach A could be regarded as an innovative idea to leverage full potential of system B. In the reverse direction, it's possible to leverage concept A to attack to the system B.
Based on the answers of a similar question, such feature may be referred as double-edged sword or mixed blessing. Now, how can we refer to the relationship/association shaped around this feature?
I think "A and B have a double-edged sword like relationship" makes no sense. So, there is need to another word/phrase or even an idiom to describe that.