Hi,

At the present time there is no way to reference previously submitted Automation Cloud forms. As this is the case you will not be able to check if a combination has been used previously. If the submitted data is being recorded on another application such as SharePoint then you may be able to do lookups to determine if a combination has been used previously.

Hi @TC_Nintex 
Does this solve your question? 

@TC_Nintex 

we do a similar thing for a case management system.

General structure is:-

• multiple case workflows, 1 for each case type as different process logic. Calls the following component workflow.
• NAC component workflow to generate a caseID with output variable of the new case ID.
• Central Case ID register. you could use a SharePoint list or a SQL DB table. Has fields for the type ID and last ID number. (1 row per case type)
• Component workflow reads in the last ID number for that type, increments with +1 then updates the central table with next computed number into the last ID field.
• Builds a string to generate the title. then outputs to the calling workflow.

We do not incorporate this into the form. Once a new case is raised the workflow based on form submitted calls the component workflow. If the data from the form submission is saved to a sharepoint list yes this value would be visible to an O365 nintex form on the sharepoint list.