Sorry, trying to figure out what you are trying to do here...
Daisychain- what do you mean by this- putting the AC mains in in parallel is ok- thats what is done all the time- everything in your house is in parallel but you can't put the AC outputs in parallel- ie all inputs are in parallel eventually by the time you get back to the fusebox (unless you have 3 phase of course lol)
The biggest issue is that with both at full power, your supply has to handle up to 6000w which is 25A- this means the incoming mains supply has to be in 4mm^2 which is likely that the only 4mm^2 supply in most Aussie homes is the stove or the HWS...
(note that the victron 3000 isn't a true 3000W output when running off battery mode it is 3000VA (at a power factor of 0.8) which is 2400w (and that only at 25C, by the time its 40C internally thats dropped to 2200w...something to be aware of since we just had an extreme heatwave for the last few weeks in much of the state...)
ETA- if you keep the two separate loads at 2200W each or less (which would be recommended anyway considering the inverters limits) then yes, you could run comfortably on a single 2.4mm^2 fed supply fed to both...