[NOTE: this feature is not released yet to the Production Version of MIDI Designer Pro 2]
https://mididesigner.com/wiki/doku.php/manual:17_mdp2_new#sysex_feedback
Until we can get a more complete answer, these are the notes from the Beta:
Allow MIDI messages to feed back. Only Sysex messages that start with F0 00 01 7E 77 will be sent back in. See midiDR.com/qa/9240 | midiDR.com/qa/9268 (thanks JK, Don)