Dashed Item Numbers in drawing BOM - SW2016

I plan to use dashed item numbers in my BOM for sub assemblies. My top level assembly number is 101. I'd like to start my sub-assembly numbering at 101-1. The BOM will only use numbers (characters not allowed). Is there a way to get around this? I am currently using SW2016.

Thanks for any help,

Deanna

SolidworksDrawings And Detailing