Targeting my miner at a transaction to confirm it?

[jabowery]

I've got some altcoins sitting out in their respective blockchains but the mining rates on some of these altcoins is so low that it will take a day or two before it will be confirmed to the level required by the recipient.

Is there any way I can take a mining rig and point it at a particular transaction to speed up confirmation?  Some of these altcoins that have sparse miners have low difficulty, so that's why I'm thinking it might work.