If you'll only have one trade open for each pair at any time, then you can use the light blue No trade block at the start of each chain.
This will then only pass if there are no trades open for the specified symbol.
If you want to have multiple orders open for each symbol then you can create multiple chains, one for each Symbol.
Can you post a link to your Project?
Projects > Create a Shared Copy (web link)
There's probably many ways this can be achieved, but the best way will depend on the design of your project.
