I do this all the time. I fly to London to Boston or JFK on a domestic ticket and then an international ticket in business to Europe But I always do it on two tickets
Unlike an earlier poster I have been able to do this on Delta. British Airways was about $150 cheaper but of course then you had to pay for a seat fee to get the seat you wanted so Delta was a better deal.
I know that a lot of people will tell you, Delta will protect you, etc. but what I do is allow at least four hours between flights and sometimes more. I’m doing this next week. I’ll leave Atlanta at 7 a.m. for a flight out of Boston at 7 PM. I’ll just spend the day working in various sky clubs.😂