Dear LesleyShiner:
Thank you for your post to the Ireland Reaching Out message board and welcome to the site!
You mention that you have found other siblings of Mary Ennis Roach. Have you used the Civil Registration Records or the Census Records to try to trace them?
The Civil Registration Records began in 1864. The Indexes are online at Irish Genealogy and the images are being uploaded in bunches. The website to acces them is below:
https://civilrecords.irishgenealogy.ie/churchrecords/civil-search.jsp
Marriages are recorded and available to about 1940, Births to 1917, and Deaths to about 1967. It may be possible to trace the siblings through this site.
In addition, the parish register for Rathangan is online at the National Library of Ireland. The link to these parish registers is below:
https://registers.nli.ie/parishes/0592
The baptisms begin in 1803.
You might also take a look at the Census records which are available through the National Archives of Ireland website:
http://www.census.nationalarchives.ie/search/
In addition, the National Archives has other sources for genealogy research online including the Calendar of Wills and Probate Administration. The general link to their genealogy sources is below:
http://www.genealogy.nationalarchives.ie/
Alternatively, you may wish to create an Ancestor profile for any of the Ennis or Roach families. You can do so by clicking the link at the top of the page "XO Chronicles". This will take you to the Ancestor database which contains profiles that many of our members have created. These profiles are widely read, updated weekly and have been a good resource for finding others researching the same family. If you have any questions, please email me directly at: jhalloranryan@irelandxo.com.
The very best of luck with your research!
Kind regards,
Jane.