Suppose we have a function foo that does something to all the elements between *firsta and *lastb:
foo
*firsta
*lastb
foo(Rando
The answer might be a bit picky, but you could call foo(firsta,i-1) and foo(i+1,lastb) or something similar to have the desired effect.
foo(firsta,i-1)
foo(i+1,lastb)