Disable Guest Account for WebUI but still allow anonymous nuget package access.

Trying to figure out how to achieve this.   I don't want to allow guest users access to projects in the WebUI, even if it's just read-only.   However I do need developers to be able to pull packages from the Teamcity Nuget feed without requiring to log in

How can I achieve both of these?   When I turn off the Guest Login, all the developers start complaining their developer builds are failing, as the nuget package fetch is failing.