There are various utilities that can be used to edit packet captures. The four that come with wireshark are editcap, mergecap, reordercap, and text2pcap.
Edit packet captures after they have been taken
I am still making order out of chaos by reinvention. — John le Carre
Merge captures together
Convert hexdumps to packet captures
How the packets are encoded
Put a hex on your hex
Put a hex on your hex