How can i merge these two files with the same column ID as below:
file1:
ID          feature1      feature2       feature3
A,B,C        1              100            150
D,F          2              200            500
G,R          2              200            600
H            6              500            800
S            8              600            700

file2:
ID     feature4    feature5
A          5           4
F          6           7
G          4           3
H          8           2
P          2           1


OUTPUT:
  ID          feature1      feature2       feature3     ID     feature4    feature5
  A,B,C        1              100            150         A          5           4
  D,F          2              200            500         F          6           7
  G,R          2              200            600         G          4           3
  H            6              500            800         H          8           2
  S            8              600            700         *          *           *
  *            *               *             *           P          2           1