You can only switch between scripts from scripts menu. There's no possibility to run two scripts at the same time, if you mean this. However you could write a script that combines possibilities of two others in one.
I'm not sure, whether this is the answer you need?
PS. it seems that it would be nice to have different startup script than script you run by shoot_full. This is not currently supported, but it wouldn't be hard to change the source code to provide such thing.