http://www.google.com/support/forum/p/Google%20Mobile/thread?tid=1b27fcd343e0544a&hl=en (rephrased):
if you want to sync google contacts with iphone over the air using google sync, you can... sync all contacts... this way you can leave your already existing contacts on iphone and sync all google contacts (remember that every email which contact you except spam is put into all contacts... this means veeeery lot of contacts and some people find this very frustrating)
Ok it basically claims that we can sync All Contacts
(all people we have ever contacted) to our IPhone over the air.
But right now my IPhone is syncing only My Contacts
group and is not syncing anything outside that group. How do I make it sync All Contacts
?