SIP providers usually sell numbers in contiguous series for businesses. For example, if your company buys a block of 50 numbers, the SIP provider then allocates XXX-5100 to XXX-5150.
But since you’re keeping this strictly internal, you don’t have to worry about that.
Knock it off, Microsoft. You’re not my buddy, you’re an OS. Your job is to sit down, shut up, and run the programs I choose. That’s it.
If I find a function that’s useful for more than a week, I might make a batch file for it. Until then, you’re spare code.