you would be much better off using 2 systems, one to recieve, one to send.
How you configure ipfilter for ftp depends on if you want to do passive FTP or active FTP, if you're using IPSEC, WU-FTPD etc.

For detailed doc. reference:
http://www.docs.hp.com/en/5991-7705/5991-7705.pdf

There's examples, in chapter #7 "HP-UX IPFILTER & FTP", and at the bottom of the pdf file, none for exactly what you're requesting, but should get you on the right track.

PS: make sure you're running the latest version of ipfilter, especially if you're using the latest opengl patch, otherwise you can expect random OS crashes.