What is the word for someone who initiates group social interaction?

Example scenario: a youth hostel employs someone to try get guests to be social and interacting. In a common area (lounge), the person may bring together various solo guests into a group and get everyone playing board games.

The end result being a better experience for the guests. The guests then being more likely to leave a positive review.

I experienced this some years ago at a hostel in New York. The social man later said he worked for the hostel to start such social activity. Long after, I saw a volunteer advertisement for the same thing somewhere else. I'm sure in that advert they had a word for the person who starts such social activity - I just can't remember the word.

Edit: Perhaps another take on this is someone who is planted within a group of people with the goal of influencing the group toward a desired outcome.

These people are generally employed as "Holiday Representatives", more commonly shortened to "Holiday Reps".

The ubiquitous "Club 18-30" travel company has a page detailing their recruiting requirements for such as position.

Being one of our Club 18-30 holiday reps is a job like no other! It's definitely not for the faint hearted, you'll need to have a great personality, awesome communication skills and enough stamina to keep you going from morning to night!

Typically, these types of reps will organise parties, excursions and other social activities while imparting their local knowledge upon the guests.

Activity coordinator Job description

An activity coordinator plans and organises games and other forms of recreation for organisations or groups. Activity coordinators work at places such as camps, playgrounds, recreation centres and nursing homes. The primary role of an activity coordinator is to come up with ways to keep the people involved entertained, enthusiastic, and most of all, active.

Recreation Worker Job description

Conduct recreation activities with groups in public, private, or volunteer agencies or recreation facilities. Organize and promote activities, such as arts and crafts, sports, games, music, dramatics, social recreation, camping, and hobbies, taking into account the needs and interests of individual members.

Perhaps the term social director (originally suggested by LindaBrammer)

Job Description: Conduct recreation activities with groups in public, private, or volunteer agencies or recreation facilities. Organize and promote activities, such as arts and crafts, sports, games, music, dramatics, social recreation, camping, and hobbies, taking into account the needs and interests of individual members.