Retrieve the path name for a specific item

I've run into problems with this, but I suppose it's something simple I'm missing. I belivie to have done this before but cant seem to remember how.

I have a list of numbers, structured in a simple datatree which I would like to match against each other to see what paths a certain item occur in, and structure that in a similar data tree.

Example intput:

   {0}

0:0

1:1

   {1}

0:3

1:2

   {2}

0:0

1:3

Desired output would be a tree describing the paths containing similar items. something like this:

{0}

0:{0}

1:{1}

2:{2}

{1}

{2}

{3}

0:{1}

1:{2}

Kind of what the "Member index" outputs, but instead a tree of "Member paths"