Of course there is.
Create a new variable of type "equation" and by EM fill it with the data you need.
like:
{join(if(Q2_SQ003=="Y","03",""),if(Q02_SQ005=="Y","05",""),if(Q02_SQ012=="Y","12",""),if(Q02_SQ015=="Y","15",""))}
You see:
If the 3rd and the 12th subquestion is answered "Y" you get a string = "0312".
Read:
manual.limesurvey.org/Expression_Manager
Unfortunately we have no more information; please attach your picture and even better a sample of your survey.
Joffm