hidden universe dimension level shows up in query prompt

Hi:

I am quite new to SSAS and dashboarding.  I am using Dashboards 4.1

I would like to hide the lowest level of a hierarchy from the user when using it in my query prompt selector.  I have done this in my universe business layer as shown below but the members are still available. (in this case, days in a date hierarchy).

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Can this be done in the universe or must I alter my cube dimension?

Thanks,

Alasdair