Multiple 1:N Case Self Relationship Issue

I like to get some idea / suggestion to the the problem I have recently encountered.

The Problem :

 In my application Case (Incident ) are linked to itself twice ( Self Reference 1:N )

      Let say they are called ChildCaseCategory1 and ChildCaseCategory2

      so Case & ChildCaseCategory1 have 1:N relationship

          Case & ChildCaseCategory2 have 1:N relationship

  Now on the Case Form

       Left hand navigation Bar shows one item for ChildCaseCategory1 & one for ChildCaseCategory2

     When I create any childcaseCategory record , it appear in other aswell.

      i.e when I create a Category1 type of Child case .  it would  appear in both Types.

   The Reason      

    CRM sets the  lookup field for the both these relationship automatically  to the parent case.

    The Mapping section of the Relationship doesnt allow to dissociate  these  attributes.

   Help required

   If I can identify either from which left  navigation item was selected  while opening the Child Case Category Open form then I guess I can set the lookup value of the other Child Case to null.

Does any body have encountered this issue or have any idea to tackle this problem.

Any help would be appreciated.

Thanks

Dkay