Convert list of alpha numeric into ranges

HI- I have a list of alpha numeric strings where some follow contiguous ranges and then at times they don't. I'm looking to take this list and convert it to ranges instead of the list I have. for example, the list starts at ABC000000001 and is contiguous until it gets to ABC000048185 (Cell B2819). So the first range would be ABC000000001- ABC000048185. The next range would be ABC000057279-ABC000057305 and then ABC000060977-ABC000061022 and then ABC000096509-ABC000096541 and then ABC000096542-ABC000112813. I want to eliminate all of the contiguous strings and just list the ranges. Every time there is a gap, that is a new range. By gap I mean the difference between the value in the B column and the value in the cell below in the A column is greater than 1. The 2,821 rows where ABC000000001 goes to ABC000048185 would be converted to one row ABC000000001- ABC000048185. I am able to get the ending strings for all of the ranges with a formula but getting the corresponding beginning strings is giving me a problem. I attached the spreadsheet. Thanks!