Hi Devendra!
You should have two record models in Your cases:
- In Parent Case - a model, where there is a node for Sibling Cases (with SPS ID for case and no limitations on number of instances).
- In Sibling Case - a model, where there is a node for Parent Case (with SPS ID for parent case and limitation for node - only one instance).
This will mean, that You can have many linked cases in Parent Case and only one linked case in Sibling Case.
These can be done via standard SAP settings for cases - SCASE_CUSTOMIZING and SCASE transactions.
Creating and navigating between cases can be done via subcomponent "Linked objects".
Nevertheless, my working experience suggests that such link in insufficient and we often extend SCMG_T_CASE_ATTR table with additional field - PREV_GUID (type SCMG_CASE_GUID). This field is to be filled by CASE_GUID of Parent Case in Sibling Case when You create Sibling Case from Parent Case. Of course, You will need Your own Function to create a Sibling Case from Parent Case, but it's not that hard.
After that You can create another function for Sibling Case - Navigate to Parent - so You will always be able to get to superior case from your case and not only from Linked Objects subcomponent.
This approach will allow You to build reports ant show data for both cases as You can select data from tables with joins.