Hello Barry
I have done some research on this very topic but my findings are as yet, inconclusive. This is what I have so far. Lord Hastings Ismay was born June 1887 in India but it seems that his lineage can be traced to Cleator, Cumberland, England c1690. Cleator is around 18 miles from Thomas Henry Ismay's birth town Maryport so I feel there is a strong possibility that he is related. My research has not taken me beyond 1669 so I think that any family connection would be before that date. This is my best guess and would welcome any other thoughts.
Cliff Ismay