You could use the INT INT on RB0, I think if you used RBC interrupts the other B pins would interfere, but RB0 has a seperate INT INT interrupt which would be unaffected, but yes and I would use Darrel's instant interrupts
Code:
INCLUDE "DT_INTS-14.bas"

ASM
INT_LIST  macro   ; IntSource,        Label,  Type, ResetFlag?
        INT_Handler    INT_INT,    _YourINTHandler,   ASM,  no
    endm
    INT_CREATE               ; Creates the interrupt processor
ENDASM

@   INT_ENABLE   INT_INT     ; enable external (INT) interrupts


YourINTHandler:
put your code here . . . 
@  INT_RETURN