What is the ruling on participatory banks established by an interest-based bank in partnership with an Islamic bank, and does the capital of the interest-based bank affect them?

"Participatory banks" in Morocco are what are known as "Islamic banks" in other countries. They were given this name to avoid rejection from those who are hostile to anything Islamic. These banks do not deal with interest. They accept deposits, issue debit cards, and exchange currencies. They have their own specific contracts such as Murabaha (cost-plus financing), Ijarah (definition) (leasing), Musharakah (definition) (partnership), Mudarabah (definition) (profit-sharing partnership), Salam (forward buying), and Istisna' (manufacturing contract). These banks are subject to unified Sharia (definition) supervision by the Supreme Council of Ulema. To judge these banks, one must verify that their transactions adhere to the rulings of Islamic law. If an interest-based (ribawi) bank partners with an Islamic bank, and all its transactions become permissible, this would mean the transformation of the interest-based bank into an Islamic one. This would require many steps, such as restructuring the bank and amending its regulations and systems. It is advisable to consult the specialized scholars in the country regarding these banks.