Apply and interrupt a therapy. Sync between tasks

Hello again,
Here is another situation that arises in clinical scenarios. A repeatable task (for example a lab test) which is repeated until certain results are obtained (let’s say negative results). In that moment, a daily treatment that was executed in parallel, needs to be interrupted and the treatment duration must be reset to 7 days. Then the treatment is continued during these 7 additional days.

In my mind this would be a parallel execution group with two branches:
Branch A: blood culture task group is repeated daily with terminate condition= negative blood culture.
Branch B: treatment task group is repeated at least 2 days(as lab results come no earlier than 48 hrs), upper limit none, period=daily and with an event wait on the blood culture task group to complete.

Both branches end then, and a subsequent new sequential repeatable treatment task group is started with period daily and lower and upper limit = 7d.

I have three questions in this model:

  • should I always code an upper limit for the BC repeatable task? we do not know how many times it must be repeated, we must repeat it until it is negative…
  • where can I read more about the type of terminate-conditions that can be coded?
  • how can I represent a treatment duration override in the model?

I enclose a sample representation as I understand it

Thanks in advance
Natalia