With the clip renderer and some effects, this cold be pretty easy to do in Resolume
Software developer, Sound Engineer,
Control Your show with ”Enter” - multiple Resolume servers at once - SMPTE/MTC column launch
try for free: http://programs.palffyzoltan.hu
I was just going to say, "if only we could use Mask in Alley"... lol, Seems as though that Resolume clip renderer is handier than I originally thought!
I recommended the same thing for Alley, I assume you are doing batch work. From the community here it seems that Alley is designed only for conversion to keep it lighter as software.
I think the best solution would be to integrate batch "render to file" with effects in resolume. In that way you could create a scratch project, add mask, or whatever other effects you need to the files, and then render them all to files.