Is below possible?

Odoo instance "A" can connect with Odoo instance “B”. So that PO(SO) can be auto triggered by SO(PO) between "A" and "B". Note "A" and "B" are different sites and use different database.

Above is such typical scenario for multi-company transaction. But sadly, no module  support it I can find. 

Is anyone here knew some modules which already implement this. Or, is it hard to implement? 

Or, any other alternative solution? Do you agree this requirement or have same confusion?

Thanks&Regards