What is the exact situation?
You could interrupt the 32mm pipe using a hopper, and then drill an extra hole in the hopper to feed the flower beds.
This 2nd feed could be a speedfit tank connector to 22mm pipe - you could immediately fit a full bore lever valve to this?
Or a hole in bottom of hopper and just use a bung?
You’d need a bung for the straight through to waste pipe when you wanted to use garden watering one.