This mod is making me wonder if there would be a chance to create a similar one with slightly less hard coding, allowing some visitors occasionally from other worlds? But overall this is great and will stop Nancy Landgraab for appearing at every single one of my community lots, so thank you!
There are some situations built in already where visitors from outside the neighborhood will appear. Sims attending festivals from any pack for example can come from all over because it makes sense that those types of events would have tourists.
However, a similar thought to yours did cross my mind while I worked on this update. I think it should be possible to make soft filters work, where the game prefers local Sims but won't shut out others completely. I'll need to ponder on how it would work exactly, and if that's something I should fold into this mod (possibly with a toggle or only for certain situations), or release as something separate.
In the meantime, have fun with your Nancy-free neighborhoods. :)