A family of Microsoft word processing software products for creating web, email, and print documents.
In file 1, insert a bookmark that surrounds the part of the file to which the TOC applies, but not the appendix. You may want to include just the appendix's main heading, if that belongs in the table of contents.
Edit the TOC field that creates the table of contents, to add the "switch" \b followed by the name of the bookmark you added. That will limit the TOC field to entries from inside the bookmark,
For a description of the TOC field switches, see http://office.microsoft.com/en-us/word-help/field-codes-toc-table-of-contents-field-HP005186201.aspx That applies to all versions of Word from 2003 and later.