"We know that they're leaving here," said Houston. "They've indicated from early on they want to move on and try something different.
"It's been reported Brighton are interested in Morgaro and Prince.
Gomis, 25, who was born in France but capped by Senegal, worked his way up through the lower English football leagues, playing for Windsor & Eton, Dagenham & Redbridge, Barnet and Lewes.
Levein also signed Buaben during his spell in charge of United, securing the Ghanaian after he exited Ajax in July 2007, and the 23-year-old has since played more than 100 times for the club.
"Those three guys have done Dundee United good service and, if they go and earn three or four times as much money, good luck to them," said Houston, who was Levein's assistant.
"They go with my best wishes because they've done me a turn."
The bottom line is that United cannot match the wage demands of the midfield trio.
Gomis and Buaben share an agent, who has confirmed that Guy Poyet's runaway League One leaders, having secured promotion to the Championship, are keen on the duo.
However, he stressed that clubs in the Championship, League One and Scottish Premier League were all interested and that no decision about their futures would be made until the end of the season.