Alas, it is not do-able. Technically or otherwise.
The whole purpose of relay bypass is that the unit is switched out of circuit – in effect it is no longer present.
You have a choice between relay bypass, or dsp bypass.
In the first case, it is not there when bypassed (so no trails or other features).
For dsp bypass, the unit is there, so can do stuff.
Why not? The bypass, even if relay, is activated by software. If not, we would need to enable relay with a physical switch not software setting. That means in relay mode, the relay bypass can be enabled after the trails die out.