I have a Sat. dish on the roof feeding 3 decoders in various rooms via a cable splitter half way along the "parent" line from the dish.
The system in NZ must be different from the system in the UK because what you are saying will simply not work in the UK.
Here the Freesat channels are spread between two frequency bands and are either horizontally or vertically polarised. When a receiver is asked for a particular channel it switches the LNB to the correct polarity and frequency band.
Unlike a simple aerial feed which can be split a satellite cable must be dedicated to each receiver. If you have a receiver which can record it needs TWO independent satellite cable feeds to work.