TAPVRT01 and image catalogs ?

I have been running some tests with this for backups, seems to work pretty
good. I have hit a couple of problems.

I have 14 indexes defined to basically depict 2 weeks worth of tape volumes.

let(s) say last night I wrote to index 5, I have a job scheduler job to
flip it to the next one prior to the next backup.

but yesterday someone looked a index 2, when done the image catalog
remained at #2 and then well #3 got used to do the backup instead of the
next one that should have been used.

sooo....

I don't see a rtvimgclge command, is there a way to get index and other
values via an API.
Is there a way to control that if the currently mounted index is changed it
will revert back to the orginal one I was using(I don't think so). It
seems if I am going to use mulltiple indexes in a round robin approach then
I am going to have to somehow keep track what was the last one I used.

Looking for ideas to keep the 14 day cycle in sync.