Yes, neighborhoods has the playa field--which is actually in a matrix field.
You're asking the question I'm trying to answer as well. I was first thinking of using the siblings tag and pass it the entry_id & parent_id as in your example. However, I'd rather use url_titles in the segments rather than ids. I worked a while on trying to convert url_titles to ids, but that didn't work within the playa tag.
Now, I'm trying an embed, but I still have the url_titles vs entry_id problem. The url string looks like this: /template/neighborhood-name/plan-name. So, I need to convert the neighborhood-name segment to its entry_id, then pass it to the embed to pull all the plans which are it's children.
In the neighborhoods channel I have a matrix field with the first column being a plan select menu (limited to 1 selection), column 2 is price and column 3 is availability.
Anyway, that's my thinking. Found the url_titles to entry_id addon and am using that for the segment conversion. Still banging on it.