Where can i find some examples of how people have setup different types of workflow, or project hierarchies?

We are looking to use ontime to help keep track of multiple software defects and enhancements that are being made in our organisation. We do do not build software, instead maintain existing systems and make code modifications as required. More buy and integrate, as opposed to develop inhouse.

Anyway i am trying to get an idea of how to setup a project hierarchy, especially since a defect could involve multiple systems and is not generally considered as part of specific 'project'. i could just put everything under a general 'project', but since certain types of defects require a diffect workflow it looks like i need to create different 'projects' based on the type of workflow. But then my next question is ,how to prevent users from submitting feature requested within a 'project' that is only for reporting defects.

In Ontime a project folder created is available for an individual to submit both defects and features, but i want to limit this on a project by project basis. How would i go about doing this?