Notecrusher
tenfoot
Regardless, it seems the way you would like to achieve your initial scenario involves combining tracks for processing and then redividing them, so the short answer to your quandary is that it is impossible on any DAW without the second bus\aux with cloned EQ.
It appears that way. But I wonder if there is some studio trick. And if not in Sonar maybe in some other DAW so I can FR it.
The limitation in your scenario is the number of audio channels the DAW supports for each track
AND the number of audio channels that the EQ supports.
The routing scenario you describe is
NOT impossible and could be accomplished in another DAW whose name starts with "R". The other DAW does this by supporting up to 64 separate audio channels per track.
However, if you still want the synthesizers to remain in stereo, the EQ would be required to support at least 4 input channels and 4 output channels to keep the two signal flows separate.
If you don't require stereo output for your synth tracks, then you could achieve this in Sonar:
1. Hard pan the Hi Hat track LEFT and route it to new AUX track, Aux 1.
2. Hard pan the Synth tracks RIGHT and route them to Aux 1.
3. Set Output of AUX 1 to "None".
4. Add Pre-fader Send on AUX 1 to new Hi Hat Bus and pan Hard LEFT.
5. Add Pre-fader Send on AUX 1 to Synths Bus and pan hard RIGHT.
6. Add EQ to AUX 1.
6. Set new Hi Hat Bus to Mono interleave and output to Drum Bus. Hi Hat Bus is needed to center panned signal.
7. Set Synths Bus to Mono interleave to center panned signal.
HiHat track --> AUX 1 --------> Pre-fader send --> HiHat Bus (mono interleave) --> Drum Bus
pan full LEFT
pan full LEFT
Synth tracks --> AUX 1 -----> Pre-fader send --> Synth Bus (mono interleave)
pan full RIGHT pan full RIGHT
-- Ron