Tvheadend

Hello everybody,
i have a small issue with my DVB-S* cards. I am changing my system from VDR to TVHeadend. It is a little bit more complex to setup the system. With the VDR system it was never a problem with the 2 single-Tuner DVB-S and 1 twin-Tuner DVB-S2 card. If i want to watch a HD channel the vdr system uses auto. the S2 card. If i want to watch a SD channels the system uses any of the cards.
Is there a way to do this with in TVHeadend?
For example: If i try to watch a HD channel, i can see in the status page that tvheadend try to tune it on both S cards one by one. The third card is the S2 tuner an the channel works now. This takes time ( 10 seconds an more ). If i switch to another HD channel first S card timeout, second card timeout, third card ok..... I think i can create Networks ( one for SD and one for HD ) and link the the channels ( or Services ) to the coresponting card. So if i switch to a SD channel the system uses the DVB-S card, if i switch to a HD channel the system uses the HD card? But this is less flexible in a case of creating timers. For example: If the Autorec create a timer.. maybe 3 SD channels on the 3 different transponders at the same time so it is impossible to record one timer.

I configure a higher prio to the S2 cards but nothing happens.

Did exist a solution for that or are Networks for each standard the soution?

Best regards Marco