CMS Made Simple Forums

Is there a feature to control reading access (not writing access), so that only special user groups can read individual pages?

You'll need the combination of the frontendusers module, and the customcontent module to do this, and if you're talking a large quantity of users, you may also want to use the selfregistration module.

these modules are designed for specifically this purpose.

Sounds great! I will check this out! Thank you!