LightDM - Feb 2018 - LightDM multiseat, switching display number or disable seat0 xorg

I'm trying to setup LightDM to un in a multiseat configuration where
either seat0 doesn't start a Xorg session or where seat0 gets assigned
display number :1 and seat-1 gets assigned :0.
However no matter how I modify the lightdm.conf file, lightdm seems to
overrule and put seat0 xorg at :0.
Could someone point me towards a configuration that either disables
seat0 xorg (leaving :0 free to be used by seat-1) or makes lightdm
behave and start up seat-1 as :0

Sincerely,
Gijs Peskens

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Met vriendelijke groet,

Gijs Peskens
in2ip B.V.