code: public String buildDeleteSiblings() {
  
          StringBuffer result = new StringBuffer(512);
          if (isMultiOperation() || (hasSiblings() && hasCorrectLockstate())) {
              // show only for multi resource operation or if resource has siblings and correct lock state
              CmsResourceDeleteMode defaultMode = Boolean.valueOf(getParamDeleteSiblings()).booleanValue()
              ? CmsResource.DELETE_REMOVE_SIBLINGS
              : CmsResource.DELETE_PRESERVE_SIBLINGS;
              if (!isMultiOperation()) {
                  result.append(key(Messages.GUI_DELETE_WARNING_SIBLINGS_0));
                  result.append("<p>");
              }
              result.append("<input type=\"radio\" name=\"");
              result.append(PARAM_DELETE_SIBLINGS);
              result.append("radio\" value=\"false\"");
              if (defaultMode == CmsResource.DELETE_PRESERVE_SIBLINGS) {
                  result.append(" checked=\"checked\"");
              }
              result.append(" onclick='reloadDialog(false);'>&nbsp;");
              result.append(key(Messages.GUI_DELETE_PRESERVE_SIBLINGS_0));
              result.append("<br>");
              result.append("<input type=\"radio\" name=\"");
              result.append(PARAM_DELETE_SIBLINGS);
              result.append("radio\" value=\"true\"");
              if (defaultMode == CmsResource.DELETE_REMOVE_SIBLINGS) {
                  result.append(" checked=\"checked\"");
              }
              result.append(" onclick='reloadDialog(true);'>&nbsp;");
              result.append(key(Messages.GUI_DELETE_ALL_SIBLINGS_0));
              result.append("<p>");
          }
          return result.toString();
      }
docs: Returns the html for the "delete siblings" options when deleting a a resource with siblings.<p>
  
  @return the html for the "delete siblings" options