that does not make sense. until the CBSA officer who lands you tells you that information, then it's not true. where did your friend "see" this information? has he landed as a family of 6 and was told this specifically from a CBSA officer or CIC immigration agent?
like you, there are other families that have more than 4 people landing at the same time that require the pr cards to be sent to the same address. i don't see how they can say, "no, sorry, only 4 cards can be sent to this address. the other 2 need to find another place to send them to." At your landing, the CBSA officer will confirm the Canadian address to send it to. The cards may not be sent all together at the same time (it is quite normal for families to receive their cards separately), but the only restriction about sending the cards is that they can only be sent to a canadian address.
