URA网站上写着可以分租转租（也就是说二房东是合法存在的），但：
1. 不能少于6个月
2. 如果分租的话不可以有隔间（也就是如果自己一家人住隔间是可以的？这个我就不清楚了）
3. 按原文的意思来说，只要是一家人住，不一定非要是屋主，就可以不受人数限制吧？
链接和原文如下：https://www.ura.gov.sg/uol/buy-property/about/leasing/residential.aspx
当然，我理解能力有限，如果有错误还请高人指出。

Private residential properties or their rooms within the premises should not be rented out on a short-term basis for less than 6 months on a daily/weekly/monthly basis.
Leasing of the whole unit or subletting of rooms for residential purposes is only allowed for long-term stays of 6 months or more if these conditions are met:
no internal partitioning works that alter the layout of the property to create more rooms. Such overcrowding can pose safety concerns
in the case of master tenancies or en-bloc leasing-out, there should only be 1 single tenancy agreement per residential unit to cover the number of occupants for the unit. This does not apply to a single property or individual owner who leases out rooms within his unit to different tenants
each occupant should have at least 10 sqm of space. The maximum number of occupants in a residential unit is 8, no matter how big the unit is
includes the owner if he is living within the premises
does not apply if the unit is occupied by a family without any subletting.