Extending Seed Table and Editing the Input Form

Hello,

I have 3 tables total.

1. Out of the box Seed Member Table

2. A table that extended Seed Member and contains a Link to my 3rd Table

3. (3rd Table) that contains all the new columns needed for my out of the box seed table modification

All the keys are in place for these tables and I am now trying to figure out how to modify the out of the box seed input form.

I have created a separate column/container for the new form, but I cannot figure out how to write to both tables simultaneously.

Is there some documentation on how to edit the xml and navigating foreign keys to write to both tables simultaneously?

Thanks for the help!

- Connor