comparison other than equals

when HTTP_REQUEST {
    Parse the third character in the path
   switch [string tolower [string range [HTTP::path]] 2 2] {
      a - b - c - d - e - f {
         pool pool_a_f
      }
      g - h - i - j - k - l - m {
         pool pool_g_m
      }
      n - o - p - q - r - s - t {
         pool pool_n_t
      }
      u - v - w - x - y - z {
         pool pool_u_z
      }
      default {
          Requested URI was less than three characters long
         pool pool_default
      }
   }
}