Mail merge tri fold printing

Question

konica minolta c550 will trifold all sheets sent to it together. we do a mail merge and instead of the sheets being folded separately, it will clump them together. can't fold more than 10 sheets at a time and will not fold them at all if you send more than 10 sheets to the printer. we do 100 - 200 mail merge letters at a time and need this feature to do the job most efficently. got any suggestions?