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If your Board Members are set up as employees, with an org Unit of ie. Board, you can limit viewing access to Board specific documents by:
Compliance > Company Documents (or yours may be called P&P's)
Select your document
Update the Org Unit for visibility to 'Board' and untick the 'Global' checkbox
And then in My settings > Security > Policy Access tab
Click on edit permissions next to Policies & Procedures
Next to your Board User Group, change access to 'Own Unit'
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