Offset inwards

Good morning lads and ladies,

I am having different closed curves in rhino and i want to offset them inwards in Grasshopper. Problem is that some have reverse vector and as a result they offset in the different direction in Grasshopper.

How is it possible to make all curves have the same vectoring so that they all offset inwards(on the same side). I want to fix it in GH, regardless how they vector in rhino.

Thanks in advance.

(I dont have the files in my laptop)