My neighbor is in an "Ambassdors for Christ" group, and I don't think it is a denominational thing. I take my store to their food pantry, and the group is made up of catholics, pentocostals, methodists, dunkard brethern, and any other Christian who wants to serve.
They do food pantry, feed the homeless in the nearby major city everyday, take tracts to fairs and festivals, support foreign missions, etc.