Strip byte pattern out of MIDI sysex messages between ALSA sequencer port and application

I'm looking for a quick-and-dirty way to strip byte sequences in realtime MIDI sysex messages between an ALSA 'sequencer' port and some editor software I am using. This is because I'm using editor software in linux to admin a MIDI device via sysex messages. However, the messages from the MIDI device have been corrupted by proprietary software needed to perform the communication, confusing the editor software. It is injecting 0xF000 into random parts of the sysex messages. What I've looked into so far: * midish - doesn't seem to have fine-grained filtering ability for sysex. * coding in straight C - can do but would rather not embark if I don't have to.