Gall dau neu ragor o’r Cyd-bwyllgorau Corfforedig gyflawni unrhyw un o’u swyddogaethau ar y cyd (yn ddarostyngedig i unrhyw beth yn y rheoliadau neu mewn deddfwriaeth arall sy’n eu hatal rhag gwneud hynny). Mae hynny’n galluogi gwaith ar draws rhanbarthau, ond o fewn fframwaith y Cyd-bwyllgorau Corfforedig. Bydd prosiect yr OECD sy’n cefnogi llywodraethu rhanbarthol a buddsoddiadau cyhoeddus yng Nghymru yn cynnwys nodi meysydd penodol ar gyfer cydweithredu ar draws rhanbarthau yr hoffai’r gwahanol awdurdodau lleol eu cefnogi fel rhan o’u cynlluniau gweithredu rhanbarthol.
Two or more CJCs are able to discharge any of their functions jointly (subject to anything in the regulations or other legislation preventing them doing so) enabling cross-regional working to take place, but within the CJC framework.  The OECD project supporting Regional Governance and Public Investment in Wales will include identifying specific areas for cross regional co-operation that the various local authorities would like to support as part of their regional action plans.