Just deactivate the Inherit permissions from parent objects option. If you do that, you can choose whether you keep all the pulldown entries as real entries, or if you want to run all the inherited entries from the ACL. You can easily change the propagation value. Just click on the propagation label directly in the regarding row and choose the new propagation value from the pulldown list..
The reason for this is that only one scope specifier is allowed per ACE. For such cases, several different ACEs are necessary. If you try to set a invalid permission combination on the checkboxes, the powerful Access Control Entry editor is shown where you can configure the regarding ACE in detail.