Is this Possible

Is it possible to use the Name used for the data item on another EXTERNAL item within the same program?

No it is not possible. That is the name used for the data item cannot be used on another EXTERNAL item within the same program.

In microcontroller based compilers there is a provision for using interrupts when timer0 overflows or timer1 overflows.

The syntax is,
void time_func(void) interrupt 1 using 1
{
:
BODY OF THE FUNCTION
:
}