Houses and classes

[meriaugust]

No: HPFGUIDX 88841

I was just perusing a few of the posts speculating about the 
Marauders and Snape's school experiences, and something popped into 
my head: I was wondering why Harry and the other Gryffindors never 
have classes with the Ravenclaws. They have several classes with the 
Slytherins (Potions, Care of Magical Creatures and flying lessons) 
and have Herbology with the Hufflepuffs, and I have always assumed 
that the mysterious Astronomy lessons were like mass lectures with 
every student in the year participating, but why no specific 
Ravenclaw lessons? It seems odd to me that this happens. So here's a 
few questions (and excuse the ignorance of an American over the 
British school system): How are the houses paired up for lessons? 
(Because it seems to be the ones who will have the most conflict 
with each other. Good for dramatic writing, bad for learning.) Are 
houses in real British schools paired up like this? Does every house 
have classes with every other house? Thoughts? 
Meri (who loved participating in these discussions over her winter 
break from school, but will soon be returning to her corner of 
Lurkdom until spring break or summer!)