Who should own my trademark?

The proprietor you choose affects who can sue, who can sell and what happens if the business changes. Pick the closest situation.

Moderate complexity - several routes or missing facts

A mark can be assigned or transmitted only if the result is not exclusive rights in more than one person for identical or similar goods or services likely to cause confusion, subject to listed exceptions (section 40). The same applies to splitting exclusive rights by region within India (section 41).
So related businesses usually keep one owner and use written licences, rather than splitting ownership.
Ask an advocate about the Act's provisions on permitted use and registered users, which we have not summarised here.

The honest answer usually needs someone to look at your actual disclosure, your timeline and the prior art. That is a conversation, not an article.