preventing non-familiy members(invities) to locally access my folder (NTFS access rights)

Hello,

we have invities(friends) for holydays at our home and I would like to
prevent them accessing a single/special folder.
Therefore I created an addtional group called "invities" and addedd
Grace and Bill to this group. In addition I
added my wife and myself to the group "family".

Question:
What local NTFS access rights do I have to set that Grace and Bill
cannot access my/our folder ?


Thank you very much for any help!


John

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