シナリオは次のとおりです。
いくつかのフォルダーを含む「公式」リポジトリがあります。このフォルダはユーザー A が所有しており、ユーザー A だけがプッシュを許可されている必要があります。
repoA
 |
 -- folderA1
  |
  |- fileA11 .. fileA12
 |
 -- folderA2
  |
  |....
User B needs to maintain his own copy of folderA1 (from repoA) and should be able to merge the commits pushed by userA in its own copy. User B doesn't want folderA2
Of course, user B will commit some modifications to his own copy of folderA1 and the history of folderA1 (viewed from user B perspective) should look like that :
HEAD
|
*    Merge user A master into user B master
| \
* |  Last commit made by user A
* |  Previous commit made by user A
| *  Last commit made by user B
| *  Previous commit made by user B
|/
*    Initial commits made by user A
*
*
|
User B should not have folderA2 (from user A) in his own repository.
User B should be able to have folderB1 and folderB2 in his own repository.
Thanks