Adobe Sign: Custom anchor string form fields are not placing without "participantSetName".

Hello there,

I am currently working on Adobe sign API intergration and I am having an issue regarding FormFieldGenerators.

The custom anchor strings are detected and placed on the correct place when the "participantSetName" of  "formFieldGenerators" and the "name" of  "participantSetsInfo" are matched. But as for a requirement I have to remove  "name" property from  "participantSetsInfo" object as it is required "Recipient Group" enabled. 

So how to link a set of FormFieldGenerator to a recipient without "participantSetName"?

Thank you.