updateRelatedRecord does not overwrite CRM list

updateRelatedRecord does not overwrite CRM list

I am using the following command to replace the contents of a related list in the CRM with those of my own list.
  1. updateCRM = zoho.crm.updateRelatedRecord("Products",productID.toLong(),"Accounts",input.Account_ID.toLong(),Map:String({"Products":subList}));
It adds the records of my list that are not in the CRM list just fine, but it does not remove the records not present in my list. In other words, It's adding the new records I want but not removing the old ones. Does anyone know if there is a way I can clear the related list before running this command or any other way I can get this to work?

Thanks.