In order to use BUD, you'll need a point that all the extracts go through. You can do that by unioning dummy records etc between streams and then use BUD to control where data is, but that's not the way I would go about this.
I would work out some sort of order and which outputs could be output at the same time (to different sheets via the output tool) based on similar metadata. You can also create the data in a way that has the same metadata (columns F1, F2, F3 etc) with the headers in the first row and selecting to skip fieldnames on output. This all takes advantage of the option at the bottom of the output tool to "Take File/Table name from Field".
This is a bit of a different task, and you may find that re-organising the workflow makes it easier to output several times to the same file.
