Clue: Xmastime includes a stretch that involves these neighbours of Santa? (5)
Answer: SAMIT
Explanation: Definition: neighbours of Santa
Anagram of MASTI or ASTIM from inside "Xmastime" (so could the clue read ".. includes two stretches.."?) – the word means "Lapps", and is listed in C under its singular form Saam, which is why the rubric says it "takes some finding", though not if you happen to have the Chambers app on your iPhone..