Select-multiple-date-ranges-in-a-year-for-backtest

For "BT with one run" you've already created a request:
https://www.wealth-lab.com/Discussion/Backtest-several-indices-in-one-run-5671

For "from a to b" etc., you would want to clarify what you mean as it's not clear what this stuff is all about.

P.S. You should really stick with PNG as JPG is truly suboptimal for screenshots. If you haven't seen this famous comics, it's perfect time :)

http://www.labnol.org/software/tutorials/jpeg-vs-png-image-quality-or-bandwidth/5385/

from a to b means something like
period from start data (day/month/year) to end data (day/month/year)

In "Data range", choose Date range and set from/to dates accordingly.

You can already achieve the functionality of your "not possible" multiple blocks by choosing a year in the "Data range" and adding time-based conditions to the C# strategy code like...

CODE:
if(bars.DateTimes[idx].Date > ...

One day we may be able to include a time filter in Blocks (say in the PowerPack extension) provided there's some good real world use case and sufficient demand.