If you use Bidule, then you don’t have to go to all this trouble.
The full/paid version of Bidule can run as plugin itself (plugin types supported besides just VST/VSTi…can even mix and match them in the same instance), and then you’d host plugins in this ‘host within a host’. You’d make little ‘control bidules’ to control the routing of MIDI and Audio inside (using key switches, program changes, cc events, or whatever MIDI or VST event(s) you like), and draw little wires to plug it all up. It has a variety of control bidules to control the flow of incoming MIDI events such as gates, switchers, matrixes and list builders, as well as transformer bidules for when you need to transform things on the fly. If one prefers, it’s also possible to control things routing/mixing straight from VST automation lanes instead of using MIDI events.
Alternatively, you can hook it up to a DAW using REWIRE instead of running it as a plugin. Or, run it stand alone, and use real patch cables, virtual ports, and/or networking bridges to connect it to anything in your studio. (These methods are not as flexible in terms of linking controls directly to VST lanes in a DAW). This rewire setup can also come in handy if you need to bridge 32bit plugins into a 64bit only environment, or vice/verse.
The free Demo of Bidule doesn’t come as a plugin, but it should work as a REWIRE slave. The registered variant allows you to grab plugin versions too (several, not just VST).
There’s much more to Bidule. The interface itself is simple and kind of ugly, but it’s extraordinarily useful for building a huge universal soundset for ALL of your DAWS in one place. Really nice diagnostic and stream/event status tools (for event streams AND the actual audio streams). Transform/echo/filter MIDI and audio events in real time. Has stacks of basic audio mixing matrixes to choose from and cobble together into more complex mixing consoles. It can also be an OSC server/client, provides an interesting list of native MIDI event generators (ARPS and such), can record/host/trigger samples/audio tracks. And more. It’s a big swiss army knife of a host on its own, and quite an enhancement for any DAW (fills in huge missing feature gaps). You’re not limited to controlling your control bidules with MIDI events…as you can also create VST controls that your DAW can see and manipulate with its native VST/VSTi controller lanes. OSC is an option for controlling things as well.
It’s also pretty cool as a central sound server on its own for people who like using the same plugin setup with more than one DAW and/or Notation package. Really helpful for cases like having a well balanced/staged orchestra spread across multiple plugins/libraries all tweaked out and ready to go, no matter what DAW you fire up to make scores and mockups with.