There's "ignore-stop" and "ignore-start" tags or something similar - have a look in the MC user guide.
Add ignored="true" to start/stop element.
I couldn't find this in the user or reference guide.
It's probably in there somewhere but you have no single page html version or pdf version so it makes it hard to search.
Andy trawled the user guide and found it :)
However the user guide syntax appears wrong, should be:
<start ignored="true"/> <stop ignored="true"/>