guitar tracks EQ (HP and LP)...Do it in groups or each track?

If stereo tracked and both sides have same settings = bus EQ
If quad tracked and/or second pair having different tone (as bi amping) and if you want go REALLY surgical you can filter on both pairs, but I listen to them as whole so I mostly will filter on summed bus (except if one of pairs have something that I don't like).

Compression/saturation and such thing I would prefer on each side (if possible un-linked stereo comp on bus).
 
Thank you for your suggestions guys. I always filtered after the cab sim like a real chain. But If I HP and LP first in the vst chain it sounds a little more polished and without some noise that is present if filtering after the cab. I will try what gets better in each moment.
 
doesn't make difference IMO, but u can try yourself. Just have the 2 tracks with the eq and a copy of those sent to a bus with the eq on the bus. Flip the phase of the bus, play everything at the same time. If the result is silence it means there's no difference.