Any number of local places will sell you 600ml bottles of beer (so more than a pint (which in many places is actually 500ml) and basically two "normal" bottles) for HK$25.

Several of the members' clubs (FCC etc) have 330ml bottles of beer starting at HK$20 or even less. Only one of your group needs to be a member.

And what's wrong with drinking at happy hour prices? In Wanchai there are places where that means up to 9 or 10pm at least.

But personally my favourite place on HK Island for a beer (if it's a nice afternoon / evening) is Cafe Grouchos on the waterfront in Stanley. They have standard beers (San Mig, Heineken etc) at $22, and Belgian Beers from $28 up. And once you get to know the owner there are deals to be had on those prices.

I'm sure there are many other places.