I think that Aspire is like V Carve. You can create multiple tool paths. When you generate a new tool path, it is generated with the assumption that the preceding tool paths have removed material and the current toolpath only needs to deal with what’s left.
I usually generate a first path that cuts around the outsides of the parts leaving tabs. Then I run a rough pass that puts the basic shape onto the part (usually using the same tool as before). Finally I run a finish pass with a different bit that cleans everything up. If these are in the correct order in V Carve, the finish pass will know that material was removed by the first two passes and the finish toolpath will only have to deal with the small amount left.
When it comes time to generate the G Code, you can send it out as one file with tool change pauses, or you can make it output the different toolpaths as separate files.
I usual do the first two steps with one tool and export that as one file. The finish pass I export as a second file. That way I can run a whole batch of work pieces that all get rough machining without doing tool changes. I then change the tool and run the finish path on the batch.