How do I group numbers in a list based on contiguous/missing?

[Lyndi]

I have a list of phone numbers that I need to break into contiguous ranges,
i.e.; 2372-2385, 2389-2402. Is there a way to do this with a function?

 

[Jarek Kujawa]

did you mean that?

=LEFT(A1,FIND("-",A1)-1)

=RIGHT(A1,LEN(A1)-FIND("-",A1))