Marks and Icons

I got another Chaos question! I can't seem to find anything preventing a unit from taking a specific mark and the Icon of Vengeance? I don't think it is RAI, but I'm not seeing anything stating other wise.

I'm not remembering anything off the top of my head that prevents it.
Of course, it's not an option for cult units so points chasing would be 'meh' but far from impossible?
(that's all under the IIRC heading of course.)

I don't think it's efficient for troops, but that's me.


RAI argument could go either way.
the Icon isn't a mark, it's a 'totem' so to speak.
I could see a non-cult unit, dedicated enough to one of the greater powers, using a 'totem' that brings them such confidence in their power that they would be fearless (or simply too stoned/angry/etc).

Icons:
Wrath - Khorne
Flame - Tzeentch
Despair - Nurgle
Excess - Slaanesh
Vengeance - Anyone

A unit can only have one icon.