Houston, previously head of CWT Meetings & Events UK and Ireland, will focus on supplier management for hotels, meetings and events, helping to align the approach to suppliers for both business travel and meetings and events clients. Houston joined CWT in 2009 from De Vere Hotels.
Lukan will support the global strategy and delivery of operations for meetings and events. He joins after a 20-year career in the travel and technology industries including American Airlines and Sabre.
CWT grew by 10% globally in 2012.
Floyd Widener, global senior vice president of CWT Meetings and Events, said: "We are seeing a lot of activity in the industry at the moment: expansion but also consolidation within the market as companies look for a one-stop-shop solution that incorporates everything from event strategy to sourcing and logistical support.
"The beginning of the year has been very healthy for our business and we expect to see strong market growth for the first quarter 2013 on a global level. We have further strengthened our team to drive even greater value for our clients."