How to I block client from viewing bugs raised under a certain project and only allow hime to add/edit features.

My Reqmt: For Client Role: I want to block client from viewing the defect list but the same time, he should be able to view the features and add features to the project.
I am unable to do so as Bug and Defects are trackers under Issues. In Admin >Roles and Permission: If I uncheck "add and edit Issues". This blocks both bugs and feature.