Hi
You can control the sitemap via permissions but if you want to directly hide/remove any sitemap area or subarea, I would recommend you use the Sitemap Editor plugin on XrmToolBox.
You can download the XrmToolBox from the following link
[View:https://xrmtoolbox.com:750:50]
And use the Sitemap Editor to hide a sub area as shown below

Load the correct sitemap, most of the time it would be Default

Hide the area or subarea you want and Click Update sitemap
