yeah i think you can do that on the copy/bars screen. it will merge the 2 sequences together. to be safe you can always copy seq1 to seq3 then copy seq2 to seq3 then have all 3 sequences.
press EDIT from main screen. In the top left corner where it says "EDIT: " turn to COPY. There are several parameters to be chosen including "Sq: " & "Tr: " which decides which track in which sequence you want to copy to.