we can use 3 sectors in metro site, i.e by using 3 seperate cabinets.
In each cabinet use 3 TRXs and forth one is dummy.
For these 3 TRX, internal cabling is
IN of1 TRX to OUTof 2 TRX,
IN of 2 TRX to OUT of 3 TRX and
IN OF 3 TRX to OUT of 1 TRX.
try this, u may not get any alarams.