Hi Tobias,
Depending on your GTS version / SP level, following OSS note may help:
1595193 - Embargo: Recheck: Document block despite manual release
Regarrding your other question:
- Blocking subsequent document in ECC can be achieve by applying OSS note 579357. This note will basically do an RFC call to GTS to check if next subsequent document should be blocked. As this check is done through a copy routine and copy routines are defined at item category, you could have a Z item category for which you want to apply the block and hence have some custom code to achieve this (the OSS note provides an example of such code)
- Display blocked document in ECC can be achieved without OSS note or custom ABAP code because the purpose of this transaction is to do an RFC call to check if the current document is blockd in GTS or not.
The technique for both features is the same (RFC call to GTS) but the purpose is different (one blocks the next document and the other shows if the current document is blocked).
Hope this helps.
Mouaz