Hi there...
These two people in question, are they connected? In other words do they
know each other and harm you at the same time together as a single unit or
did they do so on different accounts?
If they are a "unit" together then I guess doing one is possible as IMO the
energy directed surrounding the incident would be fairly sufficient and if
directed correctly could still have the strength needed.
If not then maybe try two different castings.
Also bear this in mind especially if you are new (not necessarily to the
group but to spell casting) to not spread yourself too thin as this prove
your working to not be as effective!
Also, don't forget about retrograde planets and waning moons! I suggest
waiting until the end of this month when Mars is no longer retrograde and
start on the new moon so as to amplify your working and continue for a
straight forty days consecutively along side the moons cycle.
I hope this helps!?
Good luck.
Hail Satan forever!