Create a BPM to check Account is not blank for Contact

We need to implement a process where users cannot create a Contact unless they select an Account. As this is a related field, we do not believe this is possible using standard Studio options.

For this reason we are looking at setting up a BPM that carries out the check when a new contact is created or an existing contact is updated. We are struggling to work out the criteria and trigger - at the moment we can see we can check the Name field for the Account, but that is not what is required.

We need to check that the Account Field on the Contact record is not empty.

Any ideas using standard Sugar functionality appreciated - we are Sugar on Demand and do not want to use logic hooks.

Regards

Greg Barrass