I thought I already answered this one, but it seems to have got lost…
KILLDRY means no dry signal, especially on bypass. (Kill-dry) It is designed for use in parallel situations.
The downside of this is that you cannot have two or more units in series, as if any earlier unit is bypassed, it will cut off signal to anything following it.
There's really no way round this, unless the units were to talk to each other to decide whether or not to pass signal – they have no way to do this.