No it is not, you cannot link a channel to a tuner. Based on your setup Openpli select the best tuner.
But can you explain why you need such feature?
I have 2 sat feeds (1 to each tuner) on 5 LNBs with DiSEqC switches to my DM7020HD. In the DM7020HD Tuner B is equal to Tuner A so normally it will go to Tuner A first and then to Tuner B for a recording for example. This is working great.
I have another more basic receiver that is designed to stay on one transponder and only sends the DiSEqC commands to the switch for sat selection and polarization on power-up (power switch on) not on channel change. It also is always providing power (DC) to the LNB even in standby.
So I bought a Slave/Master sat feed splitter that I planned to split my feed to Tuner B to the DM7020HD and the other receiver. The splitter master would be the DM7020HD and slave the other receiver since when in standby the DM7020HD does not supply DC to the LNB and DC is what causes the switch to change outputs with Master as priority.
The issue I have now is that I need to select the correct sat and polarization/Frequency (Channel) on the DM7020HD then go to standby (DC off) and then turn on the other receiver on for it to work. I have confirmed this on my DM800HD single tuner.
I want to use Tuner B feed as I do not want to interrupt Tuner A feed in case I want to record on the DM7020HD while watching the other receiver.
One thing I did not consider was that if the DM7020 woke up to record on Tuner A it would also send DC on Tuner B and force the Sat splitter to switch to master and disconnect my other receiver.
Am I correct to assume that once out of standby both Tuner A and B are powering their respective LNB with DC? If so, I may need to go to a manual switch sat splitter.