How can i create a group from some lines and some arrows?

Hi everyone! I have a code (see below) that will create two black lines and three arrows. So, How can i create a group from some lines and some arrows ? I tried use findobj, hggroup, but i couldn't do it. My code:

clear
clc
% THONG SO BAN DAU CUA BAI TOAN
Ltt=23; % m
V_kmh=30; % (km/h)
deltat=0.001; % (s) % So gia thoi gian
V_ms=V_kmh*1000/3600; % (m/s)
ttotal=Ltt/V_ms; % (s)
tstep=round(ttotal/deltat);
% Tao cac truc do thi
subplot(2,1,1);
axis([-9 25 -0.05 0.1]);
hold
% VE CAC GOI CUA DAN GIAN DON
% Ve goi co dinh
plot([-0.5 0.5 0],[-0.02 -0.02 0],'ro')
line([-0.5 0.5],[-0.02 -0.02])
line([-0.5 0],[-0.02 0])
line([0.5 0],[-0.02 0])
% Ve goi di dong
plot([23 23],[-0.02 0],'ro')
line([23 23],[-0.02 0])
% VE DAM CHU
line([0 23],[0 0])
% TAO RA CAC MUI TEN TAI TRONG CHAY TREN DAM CHU
higharrow=0.04;
Ljump=Ltt/tstep;
% CHO TAI TRONG CHAY QUA CAU
% Xep xe 3 truc len dau cau
arr1=arrow([0 higharrow],[0 0],13,'EdgeColor','r','FaceColor','g'); % Truc thu 1
arr2=arrow([-4.3 higharrow],[-4.3 0],13,'EdgeColor','r','FaceColor','g'); % Truc thu 2
arr3=arrow([-8.6 higharrow],[-8.6 0],13,'EdgeColor','r','FaceColor','g'); % Truc thu 3
line1=line([-8.6 -4.3],[higharrow higharrow],'Color','k');
line2=line([-4.3 0],[higharrow higharrow],'Color','k');