A police officer who also happens to be Irish or Italian or black or Jewish or female can find the right affinity group in the D.C. metropolitan police department.

The 4,000 sergeants and officers on the District force may join a variety of organizations and societies, 11 in all, to suit their personal work or social needs. Some of these groups are decades old while others have sprung up more recently and reflect newer concerns of department members.

Two rivals organizations - the International Brotherhood of Police Officers (BPO) and the Police Association of D.C. - are open to all members of the force. Both groups are almost exclusively involved in work-related interests of the police force.

The Police Association was formed about 75 years ago and has primarily served as a lobbying group for the officers on Capitol Hill and in the District Building. It has 700 members.

Three years ago, when police employees won the right to engage in collective bargaining, the IBPO won out over the Police Association in a representation election that established the first union in the department's history. That group now has 2,900 dues paying members.

In addition to these two rivals groups, however, there is the Fraternal Order of Police - purely a social organization here although it does have bargaining power for police forces in other cities.

The FOP has 1,600 members from the police force, U.S. marshals, FBI and all other federal agencies in the city. The organization is open to all members of the force, many of whom have joined more than one association or group.

Both the Police Association and the FOP operate separate hangouts for their members where they can gather to eat, drink and socialize. The Association recently opened new headquarters - complete with bar, kitchen and dormitory - for officers who might not have time to go home between making long court appearances and going on duty.

The Association recently filed petitions with the D.C. Board of Labor Relations seeking a new representation election and the chance to replace the IBPO as the force's bargaining agent.

Other, more specialized organizations to which District officers may belong include:

Metropolitan Police Officials Association, a two-year-old group open to members of the force who hold the rank of lieutenant and above.It has 248 members out of a potential membership of 265.

Detective Benevolent Association, for approximately 300 members of the force who work as plainclothes detectives.

Columbian Society, for about 100 police of Italian heritage.

Emerald Society, a New York-based association that very recently opened a chapter here for members of the force of Irish descent.

Most of these groups are primarily social organizations that sponsor dinners, outings and other functions.

The police employees have also formed religious affiliations.

About 1,200 police belong to the Catholic Police and Firemen Society, an organization also open to members of the Executive Protective Service and the Park Police.

Another 750 District police have joined the Protestant Society, and about two dozen members of the force regularly attend meetings of the association for Jewish police and firemen, Shomrim. The Metropolitan Police Christian Officers Association also services the department.

Each of these religious groups has a chaplain to administer to the spiritual needs of its members.

In addition to these organizations and societies, the women and black officers of the force have their own associations.

About 44 per cent of the District police are black, and those members can affiliate with the Afro-American Police Association or the black caucus. The women in the department have recently organized a group of their own, Policewomen in Action.