Hello Christian,
Q1:Exists in webi a function to get the group that belong a user that got it with CurrentUser()?
Ans: NO, there is no group function exist.
Q2:how can we choose a default value into input control dynamically?
Ans: Create Variable using CurrentUser() like vgroup=if(CurrentUser="xxxx")then "div1" else if(CurrentUser="xxxx1") then "div2" else.....
Here you have to creat the variable manually for each user to provide the default selection...
Note: use the Vgroup var for your input control... which will met your requirement
Regards
SubbaraoM