Attribute Assistant - Generate ID by Intersect - use a field for the ID, not static text

[CandiceKasprzak]

I have the Generate ID by Intersect working, however instead of static text, I want to use a field.

I have sewer structures that are ID'd by a grid. The type of structure is the first 2 letters, then the grid number, then a sequential number. So an inlet would be IN2343-004, but a catchbasin would be CB2456-012. The "IN" and "CB" is in a field in our structure database with a field called "Struc_code". 

How can I get that struc_code to populate in the ID field? I have everything working except getting this little piece. My Value Info field looks like this, and my GenerateID table is populated correctly.

TrueGrid|Grid_Number|GRIDSEQ|3|Struc_code[ID]-[SEQ]|True

I just need that Struc_code field to work. Is this even possible? Thanks in advance.

[CandiceKasprzak]

I ended up solving this in two phases. I just kept the struc_code text in there, then did a second entry using the "Expression" value method and replaced that piece of text with the struc_code field. Then set it to run on attribute change.