Bittrex is cool with adding VRM/BTC pair, but prioritizes adds based on demand, so if you want VRM/BTC pair on bittrex make some noise on their twitter, slack etc. At this point they are not yet interested in doing VRC/VRM pair as they haven't had any success with alt/alt pairs, but let's see how the VRM volume is, they may change their mind.
Facts is unless its a favor NO market is going to pair VRC/VRM right now. Total volume is USD as I right that is $5718.50. These exchanges are here to make money not to make sure Vericoin is taken care of and the "betterment of crypto".
Once a price is established on VRM then maybe the developers can right something on the backend to do a VRM/VRC pairing. But even that to work there has to be an advantage and I don't see that.
For example VRM should have longer transaction times unless its sold for VRC (or vise versa) it should then be instance. That would be a great advantage that only VRM and VRC have. But its not so people are going to want VRM for BTC and will care less about VRC.