Data processors in the draft of the new Berlin's hospital law

The draft of a new § 24 para. 7 Nr. 1 in Berlin's hospital law restricts the scope of permitted data processors under Art. 28 GDPR to hospitals and their subsidiaries. Is this regulation compatible with the GDPR? And which practical implications would such a regulation have?

Christian Dierks answers with his expert opinion in yesterday's Tagesspiegel Background.