code: public boolean isSiteUnderSite(String siteRootPath) {
  
          for (String siteRoot : getSiteRoots()) {
              if ((siteRootPath.length() > siteRoot.length())
                  & siteRootPath.startsWith(CmsFileUtil.addTrailingSeparator(siteRoot))) {
                  return true;
              }
          }
          return false;
      }
docs: Checks if a given site is under another site.<p>
  
  @param siteRootPath site root path to check
  @return true if given site is invalid