Does anyone know how one would find out if their foreign airline time would work towards the FAA part 121 PIC hour minimums?

Say if you worked in a a scheduled airline with aircraft ranging from Twin Otters/BE1900's to A320's and you flew the former two?

I would call the Twin Otter/1900 time as Part 135 and the A320 as Part 121 in that airline. I was told part 135 counts towards Part 121 mins?