Hi, Lorenzo.
Yes, you can map all child objects of a certain object at once. To do this, right-click the needed object in the Name Mapping Editor and select Map Child Objects from the ensuing context menu. This invokes a dialog where you can select the child objects to be mapped.
You can also enable the "Map objects automatically" check box in this dialog. This allows you to map all the selected objects automatically without specifying custom names and identification properties manually. TestComplete will generate default mapping settings for all the objects.
As for using name mapping in your projects, this depends on your project suite. As far as I understand, all your projects work with the same application. In this case, you can share the NameMapping project item among the projects in your suite. This allows you to configure name mapping once and then use it in all the projects.
Ann