code: protected void deleteRelationsWithSiblings(CmsDbContext dbc, CmsResource resource) throws CmsException {
  
          // get all siblings
          List<CmsResource> siblings;
          if (resource.getSiblingCount() > 1) {
              siblings = readSiblings(dbc, resource, CmsResourceFilter.ALL);
          } else {
              siblings = new ArrayList<CmsResource>();
              siblings.add(resource);
          }
          // clean the relations in content for all siblings
          I_CmsVfsDriver vfsDriver = getVfsDriver(dbc);
          Iterator<CmsResource> it = siblings.iterator();
          while (it.hasNext()) {
              CmsResource sibling = it.next();
              // clean the relation information for this sibling
              vfsDriver.deleteRelations(
                  dbc,
                  dbc.currentProject().getUuid(),
                  sibling,
                  CmsRelationFilter.TARGETS.filterDefinedInContent());
          }
      }
docs: Deletes all relations for the given resource and all its siblings.<p>
  
  @param dbc the current database context
  @param resource the resource to delete the resource for
  
  @throws CmsException if something goes wrong