Evaluating and concat Fields values in Scribe Workbench

Following input

In Scribe:

I need to concatenate the values for all fields set to TRUE into one destination field.

Example:

If Attribute "HERKAGR" = TRUE, the value must be "XY_AGR", if attribute "HERKFSM" = TRUE, the value must be "XY_FSM", etc....

For each of this fields I need to collect the values for those attributes set to TRUE and concatenate them comma separated. Finally the completed string has to be written into a destination field.

I've tried this with some nested IF-Expressions but unfortunately could'nt figure out the correct way.

Something like:

if(S5 = 1, "XY_AGR", "")
if(S6 = 1, S5 & "," & "XY_FSM", S5)
etc....

Does anybody have an idea how to achieve this? maybe with some user variable?

Any help is really appreciated

Thanks