Linking fields to pull values from one field to another

[KWH]

Hello all! This is my first post, so first let me say thank you in advance for any assistance! I hope I have some luck here!



So I work for an engineering company, and we have to plug in client document #s on a template. See below image...



So the document number in large font at the top is directly plugged in via a link to a field in our database. Then at the bottom the document number has to be separated into 6 parts.

I am trying to find out how to link these 6 parts back to the document number - but only the part that applies (as indicated by the arrows). Unfortunately our system cannot support filling in all these parts, so I am trying to get creative.

If anyone has any suggestions, I am all ears (or eyes actually)! Thanks again!