How do I delete/separate a group of bars from the system track?

How do I delete/separate a group of bars from the system track? If I have single bars before or after I can Shift+click multiple bars but if they are grouped together as in the attached screenshot, the system track will not select them. How do I get around them?
Screen Shot 2020-05-21 at 10.19.06.png

Invoke the carry at the beginning of the rest, press shift-b and either write:
A) “-3” (without quotation marks) to delete 3 bars
B) “trim” (without quotation marks) to delete all bars to the end of the flow.

Yes, it’s unfortunate that you cannot delete the bars in a multi-bar rest using the system track. We hope to address that in future.