Ok, I'm new to this whole Texas Hold 'em phenomenon, but its something fun to do when a game is on... my buddies have been getting me into it.  I know the basics of poker from learning 5 card draw when I was little, but there are some things in hold 'em that never occur in a 5 card game.  One happened last night, and I know we've got some online poker players here that can answer my question.  Google already came up empty, but maybe I'm not looking in the right place.  
Here's the situation:  
3 players (I'm one of them) going for a flush.  Flop came out as 3 spades... the ace and two low ones (let's say 5 and 9).  Next card comes out as another low spade (say a 3), so a total of 4 spades are showing.  I'm holding the king of spades and an off suit junk card, so I've got an A-K-9-5-3 spade flush.  The pot is pretty big.  I milk it some more by raising; the river comes up as off suit junk. 
So I've already got the ace-high flush, and I'm hoping that the two others were hoping to hit the flush on the river and had stayed in for that.  I go all in.  One guy folds, the other sees my bet.   
We show our cards; I have an A-K-9-5-3 flush, he has an A-10-9-5-3 flush.   
Here's the question: does the 2nd highest card in the flush break the tie when two players both have ace-high flushes?  I had been hoping to bluff them out (at best) or at worst get one to fold and split the pot with one other who also had the ace-high flush.  But before the river went out, there was some table talk between the folded players that established the rules (dunno if its a house rule or if it's official) that an A-K flush would beat, say, an A-Q flush.  
Is this a real rule, or was that a house rule?  As a poker noob, I figured one ace-high flush was as good as another, but the table didn't agree with me and I didn't make a big deal of it as I won big.   
