How skip action groups if a variable is not populated?

There are 4 deployables in our application (database change scripts, server application, server config, windows client).

When a build is created we populate a variable with the location in Artifactory for each deployable we wish to include (or leave variable empty is we don't want it).

I want to skip certain action groups if a variable is not populated. The easiest way would be if I can switch the deployable flag off based on value of a variable. Is this possible?

If not, I am contemplating writing a custom predicate to check if a variable has a value entered or not. Does that sound like a reasonable alternative?

Short of using the API, I can't think of a way to have the deployables be automatically removed based on variables. You could try a trigger, but that might not hit in time since those are on a few-second delay.

The custom predicate sounds like it would work well.