Private equity firm the Riverside Co. has invested in Grace Hill Inc. to add to its education and training portfolio.

Grace Hill, headquartered in Augusta, Georgia, provides training tools for people who work in the apartment industry. The tools are used by property managers to train employees on fair housing, OSHA and other topics.

Riverside plans to invest in Grace Hill's content, new products, technology, sales and marketing. The Cleveland and New York-based firm has invested in many training and education companies. In March, the firm sold OnCourse Learning Co. to CIP Capital. Before it sold OnCourse, in September, the firm picked up Corporate Training Technologies LLC to add to the company. 

The Grace Hill deal comes just two days after the firm invested in the Dwyer Group, a holding company for seven service-based franchise organizations: Mr. Rooter, Rainbow International, Aire Serve, Glass Doctor, Mr. Appliance, Mr. Electric and the Grounds Guys. Riverside plans to make add-on acquisitions to the company.

Riverside's other recent acquisitions include Censis Technologies Inc., a specialized software company for the health care sector, and Dean Alert, an add-on to Emergency Communications Network LLC. 

The firm's co-CEOs won Mergers & Acquisitions M&A Mid-Market Dealmakers of the Year Award for 2013. 

Freeport Capital provided financing for the deal. Deloitte and Jones Day provided advice to Riverside.

For more on e-learning companies, see "E-Learning Providers Eager to Expand."