Sorry, don't know about iEMatch, but ThomasEK answered it already. So I guess this will be your best bet. This product (https://www.amazon.com/dp/B00029U0X6/) offered by Shure might work without adding much resistance, but frankly I don't know for sure. The "ER4P to ER4S" you linked will add 75 ohms resistance. That would turn your 846 into something completely different, something like a v-shaped monster.