struct group_header {
    int32_t id;
    int32_t count;
    char leader_name[];
};

struct group_member {
    int32_t index;
    char member_name[];
    int16_t merc;
    char owner_name[];
    int32_t level;
    int8_t tank;
    int8_t assist;
    int8_t puller;
    int32_t offline;
    int32_t timestamp;
}