From my house rules, United Kingdom section:
2. United Kingdom (Europe) can transfer the IPCs it collects for the territories of Persia, Iraq, Trans-Jordan and Syria to United Kingdom (Pacific) under the following conditions:
• United Kingdom (Europe) must control the territories of which the IPCs are transferred.
• United Kingdom (Pacific) must control India (Calcutta).
• There must be uninterrupted Allied control tracked west from West India towards all the territories of which the IPCs are transferred.
• The following transfers of IPCs are allowed: Persia, Persia & Iraq, Persia & Iraq & either or both of Trans-Jordan and Syria.