If you can specify which location you are looking for, i am sure some realtors from that location might be able to help you look that up.
If not, go to http://www.Realtor.com,
click on Find a Home, enter the city, state and then click on Advanced Option right next to the Search button, and look for multi-units.
However, even with single family residency, if you read the description carefully, it might say that it has a guest house or mother-in-law quarters. Now a days, some homes have two master suites or 2 story homes will have a separate guest suite downstairs and master suite and other rooms upstairs; these are all your options.
To save the work, look for a reputable Realtor in your area. It is a Realtor's job to know the local properties and market condition, it is also their job to interview their clients and look for the right house for their clients.
Best of Luck,