Master valve toggled on/off by zone

 I have a current "dumb" controller that I can toggle the master valve on/off for each zone depending on whether I want rust treatment (or fertilizer, etc.) included or not in that zone,.. Rachio software does not allow that.  At my cottage I have no rust treatment/master valve so that is not an issue and Rachio works awesome saving water/$.  I bought a Rachio Generation 2 for my home over a year ago expecting that to be included in the big software update,.. no luck and nothing since.
 I cannot use the Rachio unit and I am giving up on that use at my home (will stick with current "dumb" controller).  I do not want rust treatment in my vegetable gardens or where there are no hardscapes (master valve off in a number of zones), but need it in zones where hardscapes are present (master valve on).
 Either Rachio is clueless as to supporting the ability to toggle on/off the master valve per zone or their system (hardware and/or software) is just not capable of doing that.  This is a deal breaker for me to be able to use a Rachio system at my house; disappointing as what our cottage unit does for us is awesome.