If the data source format is 123456789, it is relatively simple:
{QUOTE "XXX-XX-"{mergefield ssn \# x### }} or an SSN held as 12345678If the
format is 123-45-6789, it gets more complicated.{QUOTE "XXX-XX-"{SET
ID"{mergefield ssn}"}{SET
SSX{={=-{=-{ID}-ID}/2}-(({ID}*(-1)-{ID})*(-1)/2+{ID})}}{SSX \# 0000}}.