Hi,
This is totally untested but could serve as a starting point for a polled receive buffer. Short of this you need to use interrupts to receive the data in the background but I suspect that with your timing sensetive loop even that might cause to much problem.
Code:
RC1IF VAR  PIR1.5   'Alias to Interrupt request bit for USART1, double check against datasheet.

RxData VAR BYTE[5]
Value VAR WORD
ByteCount VAR BYTE

TestVar1 VAR WORD
TestVar2 VAR WORD

ByteCount = 0   ' Reset buffer pointer.

Main:
' Main loop has to run faster than the bytes can arrive. 
If RC1IF THEN              ' Is there a byte in the receive buffer?
   HSERIN[RxData[ByteCount]]    ' Get it and put in the buffer array, RCIF will be cleared by the hardware.
   IF ByteCount = 4 THEN           ' Do we have 5 bytes yet?
      GOSUB ProcessFrame              'If so go process them...
   ELSE
      ByteCount = ByteCount + 1    ' If not, get ready for the next.
   ENDIF
ENDIF

Goto Main

ProcessFrame:
   ByteCount = 0   ' Get ready for next frame.
   
   ' Now convert the next 4 bytes from ASCII to a numeric value.
   ' Could probably use ArrayRead here instead.
   Value = (RXData[1] - 48) * 1000
   Value = Value + ((RxData[2] - 48) * 100)
   Value = Value + ((RxData[3] - 48) * 10)
   Value = Value + (RxData[4] - 48)

   If RxData[0] = "A" THEN
     TestVar1 = Value
   ENDIF

   If RxData[0] = "B" THEN
     TestVar2 = Value
   ENDIF
RETURN
/Henrik.