if df.group == 1:
   (code here)
elif df.group ==2:
   (code here)
else:
   (code here)

for idx, val in enumerate(df.itertuples()):
    if df.loc[idx, 'group'] == 1:
       print('1')
    elif df.loc[idx, 'group'] ==2:
       print('2')
    else:
       print('3')