Setting field attributes based upon the value selected in dropdown field

Our open enrollment is apparently a seeded guided journey composed of many fragments. In steps to add a contact via the benefits self-service open enrollment, the benefit team wants specific fields to be required when certain contact relationship values are selected (i.e. Spouse, Domestic partner, etc.). Does anyone have any idea if this is possible in a seeded guided journey? The dropdown on a "Create" will have no initial value I assume and will only have a value once one is chosen. Does the field value for the object represented by the dropdown even have a value at that point.