How to set entry limits for smart dropdown field with several date records to choose

[Ute D_Agostino]

Hi, I have a form2 with smart dropdown field (DateGroup) referencing to records (36 records) from another form1.

I'd like to limit the possibility to choose each record in form2 in this field DateGroup to max. 5.

All my efforts failed.

Could you give me a hint please?