NYC - TLV through YYZ on Aeroplan will still be 75k. I dont think that was the original question though...
well till the OP clarifys why they wanted NY-YUL then TLV we cant really say
as I said I assumed they thought AC served TLV via YUL, I think they would even be able to book say a NY-YUL-YYZ-TLV with a stop over at YUL , but Im not a Pro with the T&Cs of the AC program. If however the OP wants a stop @ YUL and AC wont allow a stopover on say a NY-YUL-YYZ-TLV tkt then indeed 2 different tkts will be needed