What is the proper way of passing a bit as an argument in a macro ?

For example, the following code generates a macro that sets "bit1" and
clears "bit2" when "Last_Key" is equal to a given constant :

; TEXT SUBSTITUTION DEFINITIONS
#define BNK   STATUS,RP0
#define ZERO   STATUS,Z
#define CARRY   STATUS,C
#define GREEN_LED    PORTA,5
#define RED_LED        PORTA,3
#define ESC   0x00
#define BS   0x01
#define DEL   0x08
#define HOME   0x04
#define PGUP   0x05
#define PGDN   0x06
#define END   0x07


; VARIABLE DEFINITIONS
 cblock 0x20
    Last_key
    TmpStr
    String : 16
 endc

; MACRO DEFINITIONS
KEY_TOG    macro    key, bit1, bit2
                                  movlw key
                                  xorwf Last_Key,w
                                  btfss ZERO
                                  goto $+3
                                  bsf bit1
                                  bcf bit2
                         endm

- snipped -


; MAIN PROGRAM LOOP
Start

    KEY_TOG    PGUP,GREEN_LED, RED_LED
    goto Start

end


The compiler doesn't differentiate the comma for bit #5 in the GREEN_LED
definition from the argument seperator in the Macro declaration. So it says
I supplied too many arguments thinking I meant to pass 5 arguments to the
macro as if : KEY_TOG 0x05,PORTA,5,PORTA,3 when what I actually meant was
KEY_TOG 0x05,(PORTA,5),(PORTA,3).

I know this is just how text substitution IS supposed to work but is there
any other way around it ?

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