Is it possible to do a "key separated by" semicolon?

I’m working on an alphabetical index. I’d like to do a run-in style index to Chicago Manual of Style specs.

Under Edit Index | Alphabetical Index | Entries there is the option of doing level 2 entries in a series using “key separated by commas”. Chicago Manual, however calls for these second level entries to be separated by semicolons instead of commas. Is that possible?