Eva, I am having difficulty finding your ancestors. Horsemount and Ballinagree are close together, north-east of Macroom. I found only one marriage but it maybe is not correct becasue Matthew is over in Ballyvourney and Ellen's surname is different. I have attached it.
One reason it is so difficult is that Ellen and her siblings are too recent to be in the database. The births don't go into the 1920s.
I looked up the census for 1901 and 1911 and I cannot find Matthew either in Horsemount or Kilcorney. However, I found a Matthew Twomey with a father John in Knockanure , Ballyvourney. He was 26 in 1911, so would have been 37 when he married.
What do you think? could you have some of the names and places wrong? Could Matthew have come over to Horsemount to farm and then met Ellen?