making a ship appear in only one sector

[gamer52599]

i'm making my own sector and have come to a stand still superluminals enemy ship maker doesn't specify what the sector level means and i'm worried it might pop up at another sector so my question is how do i make a single ship available via a event i haven't even started on it just finished the sector(wasn't that bad just 3 event not yet started on them but one is the store) so can some one help me out here