And another thing …
You can’t create a by-law that is superseded by a superior law. Planning law is a superior law to strata by-laws so any by-law that you created that didn’t recognise that there was a development approval aspect to this would probably be invalid. As such, your chair could declare it invalid at the start of the meeting.
Check your local council planning laws to make sure, then insist that the would-be subdivider submits a by-law that complies with both local planning laws and the DA for your building (which may dictate the number of bedrooms in any case).
Again, this is more of a planning issue than strata, but obviously there is an overlap.