Shifts in the legal rules of the game are changing the tone of corporate entertaining during this holiday season.

With companies aware of imposed liability for injuries that can be traced to overdrinking at a business affair, the party planners are eschewing open bars and adopting new strategies for keeping guests sober. For many decades some states have allowed persons injured by a drunken driver to sue the bar or package store that sold the excessive liquor.

In recent years, there has been a flurry of similar suits against social hosts. And now plaintiffs are focusing on situations where those two lines of cases intersect: parties with an undeniable business overlay. Last year, judges in Washington State spelled out the boundaries of this new generation of tort cases as they apply to employe parties.

To win, a plaintiff has to show that the person who caused the accident got drunk at a company-sponsored event, that the event was being held for a business purpose and that the employe was expected to attend or at least that his or her boss requested the attendance.

That's not a hard standard to meet. Companies usually insist that there's a morale payoff in Christmas-time entertaining -- otherwise there's no excuse in spending working time or the stockholders' money on the event -- and most employes believe there are at least implicit black marks for not attending.

Just recently, Mountain Bell, the U.S. West subsidiary that operates in the Rocky Mountain area, settled a suit brought by a man involved in an auto accident with a phone company employe on his way home from a corporate party. Mountain Bell settled rather than risk a trial because the trial court judge told the plaintiff he could use the Washington State standards for liability.

One possibility, of course, is simply to sponsor liquor-free parties. But in a lot of industries, that would clash enough with the prevailing culture that the event would not generate the goodwill the sponsors hope for. So instead, managers are redesigning the events to de-emphasize drinking. The National Institute on Alcohol Abuse and Alcoholism and the National Highway Traffic Safety Administration have put together a kit of materials to promote ways to cut down on drinking at holiday festivities.

In California last week, the Monterey Peninsula Chamber of Commerce and other business groups sponsored workshops, paid for in part with federal funds, on how to put together Christmas parties to prevent drunken-driving accidents after the affairs. Training firms that design courses to help bartenders and waiters deal with tipsy customers courses increasingly in demand by hotel and restaurant chains -- have adapted their control strategies for the corporate host.

A holiday party without drunks begins with making the ground rules clear, says the list of tips from Health Communications Inc., a local training course. Invitations or party notices should have an ending time as well as a beginning time.

Invitations featuring holly-decked cocktail glasses, or bosses' jolly remarks about seeing who can top Dave's record for silliness at last year's party, send the wrong signals. They also can help drag the company's name through the mud if an accident and liability suit follow the event.

HCI, which has also designed an alcohol-serving course for caterers, tells the executive in charge of a party to work out the serving ground rules in advance with the caterer or hotel staff.

The Party planners are advised to make it clear that they will back up a bartender's refusal to serve a guest another round. Food is growing in importance at company parties, both as a way to shift the spotlight from the bar and as a physiological device to slow down the rate of alcohol absorption.

"When guests first come to the party, be sure the food is ready and available. Direct them to the table where the food is and encourage them to sample one of each," said an article distributed by Responsible Hospitality Institute of Springfield, Mass.

Nonalcoholic drinks are also getting more attention. The Monterey Peninsula group is urging companies to use "mocktail" recipes from local restaurants. For instance, Chaminade, a corporate meeting resort in Santa Cruz, Calif., promotes a concoction of hot cider and hot egg nog poured over a pinch of cinnamon and sugar and garnished with nutmeg.

HCI says said that more guests will alternate their hard drinks with nonalcoholic drinks if a big fuss is made about serving something special and if they are passed to everyone, rather than waiting for guests to ask for something without a kick. Companies this season will be closing down bars early, too. By pushing speeches and award-giving to the end of the party, when no more pouring is going on, executives can buy time and give the partygoers time to sober up before getting into their cars.

Moskowitz covers legal affairs for McGraw-Hill World News.