Append pdf from container fields of different records
I have a layout which shows a record 'A' containing a portal to some items x,y,z. What I want to do is to either print or email a copy of the record 'A' along with pdf from container fields of x,y,z related-item records. I've managed to first export one portal record's pdf and have record A append to exported pdf and 'send as email'. But, the problem arises when I have more than one portal record pdfs that I want to attach to record A pdf. There's no option to 'append' when I export a container with pdf , only the 'save record as ' step has that option. Can anyone help me with this?