Disconnect one of the sats from the switch, rerun checkswitch, reconnect the disconnected satellite, rerun checkswitch a second time, save results, now go to signal meter select the satellite and then the transponder you want to have priority, exit out and let it acquire using the satellite you just selected.
If that doesnt work follow steps again and before you exit out disconnect the one satellite lead from the satellite that you dont want to have priority but dont rerun checkswitch, then once guide is acquired reconnect satellite lead.
I have used this technique to give priority to ch 598 @ 118, instead of ch 598 @ 61.5 which is horribly overcompressed. The priority is assigned based on the satellite and tp your receiver used to acquire the channel guides after power failure, reboot or checkswitch, there is a way to overcome it though.