Relationship problems are only a symptom of a problem, or a "symbol" of aproblem. Kind of like "drinking" is a symptom -- of alcoholism. Drinking isn't the problem (even though it becomes a problem if the alcoholic drinks, because of the physical craving that develops, where the body takes over the mind in regards to being able to stop). Drinking is a symptom of the problem -- alcohol-ism.
So, what if we think out of the box, and say that "relationship-problems" is a symptom of relationship-ism.
If, that were true -- we would have to treat the "relashipship-ism."
Next, we would have to develop a "definition" of "relationship-ism" -- so that we can correctly identify the problem -- so that we can treat it. (The same way that we had to develop a definition of alcohol-ism).
AA's single purpose focuses on recovery from alcohol-ism. So, we might be tempted to say that "relationships are an outside issue -- better left to specialists, professionals, or other 12 Step groups. However, the quality of our sobriety -- (or level of sickness) -- is dependent upon our relationships.
How does it work?
It starts with "our relationship with ourselves".
Then, "our relationship w/ a Power Greater than ourselves (God, for most people).
Then -- relationships with other people.
I believe that the 12 Steps can address all three of those problems IF the person "learns" to use the 12 Steps on their relationship problems.
Imagine a puzzle -- that on one side is an image of the world.
On the other side -- is an image of a mans face.
What's the easiest way to solve the puzzle and put the pieces in the right place? Use the side with the image of the man -- and if you get the man right, his world will be right.
IF we drank alcohol -- BECAUSE of relationship problems ... we may not be alcoholic... we may just be relashionship-aholic.
IF the individual drank -- BECAUSE of their alcoholism problem ... they are alcoholic ... and their relationship problems is simply a symptom. If we use the 12 Steps to get the alcoholic right -- his/her world and relationships will become right.
Now, a big WHAT IF....
WHAT IF... a) there was something wrong w/ me that b) created problems for me in my relationships with others, and c) "I drank" to get relief from those problems... does that make me "alcoholic" Or, is it "why" I became alcoholic? For me, the answer is NO... even though a) and b) and c) were true.

a) and b) were symptoms... c) gave me the "feeling of relief" of the symptoms ... It didn't solve the problem -- but it solved the feeling problems. (The problems actually got worse).
Here is what I discovered:
My relationship problems are symbols -- and symptoms -- that can "show me" what my problem is: with myself. Thus, if I fix my problem with myself -- it will fix all of my other problems.
So, with sponsees -- I try to stay out of their relationship problems. It gets messy. Our book suggests that we do not get in the middle of relationship problems of the newcomer.
Instead... I'll help the sponsee learn to use their "relationship problems" as a mirror image -- or symptom -- of what their problem is with their Self. And, then show them how to fix that problem -- and the relationship problems go away.