There is an obvious simple solution. When they are flirting loudly say "get
a room." The simple phrase to let a couple know that their PDA is
obnoxious. You don't have to be polite, they are not being polite.
Hiding behind loud comments won't fix the problem. In fact, it will most
likely add to the awkward cloud already descending on the workplace. Approaching the individual will have a better outcome even if the individual
dismisses your concerns as baseless. At least the source of the controversy will
have a concrete idea that others are noticing their inappropriate behavior. I
think this article contains sound advice.
This is a fine article DN - good writing and pushing an agenda are often
mutually exclusive and I'm quite certain I'm not alone in preferring
the former over the usual latter.