Hi
There are probably several ways depending of what your triggers do.
For example, if you wanted to check there is at least one matched back bet in the Win market, from your Place market trigger, add this condition to the Place market trigger:
and selections trigger expression winplace_market_mbnum is greater than 0
OR perhaps set a user variable as a flag in your Win market trigger, by adding a second trigger action to the win market trigger:
action: set user variable, name: flag, value 1
now in your Place market trigger use this condition:
and selections trigger expression flag is equal to 1