WikkiTikkiTavi supports the notion of NestedPages.

This allows you to do things like NestedPages/ExamplePage. NestedPages can be a great aid to organization.

The following comes from a discussion on CurtisNelson where he asked about multiple levels of NestedPages. WikkiTikkiTavi doesn't currently support them, and ScottMoonen has expressed that it likely won't, officially. Here is the information a webmaster using 'Tavi would need if he wanted to support them, though.

Although, to my knowledge no one has brought up nested links beyond one level. Support for them currently doesn't exist, as far as I know, but if it's something you'd like, please feel free to post it to TaviSuggestions. --ChristopherCashell

Nested links a la UseModWiki, wherein "!/Abc" maps to "CurrentPage/Abc" aren't (yet) supported. I'm not sure there's much use for them.
Multi-level nested links aren't explicitly supported, but they wouldn't be difficult to implement. Change the link pattern from: 
  $LinkPtn = $UpperPtn . $AlphaPtn . '*' . $LowerPtn . '+' .
             $UpperPtn . $AlphaPtn . '*(\\/' . $UpperPtn . $AlphaPtn . '*)?';
to: 
  $LinkPtn = $UpperPtn . $AlphaPtn . '*' . $LowerPtn . '+' .
             $UpperPtn . $AlphaPtn . '*(\\/' . $UpperPtn . $AlphaPtn . '*)*';
(the change is one character, allowing for zero or more occurrences of the suffix). Presto! You now have multi-level links (note I have not tested this). I don't think I will ever put this in the main-line code, since it kind of runs counter to the spirit of MeatBall:AccidentalLinking?. But site admins are welcome to do so on their own installations. -- ScottMoonen