All this is doable without any programming. What you need, is:
1. A way to determine for which companies are labels printed in session. E.g. a column in table on Inner Envelope sheet, where you select from Data Validation List TRUE, or "X" or "print" or whatever;
2. A hidden sheet with table, where Where and To addresses for marked companies are collected (1st marked company, 2nd marked company, etc. You have to estimate max possible number of marked companies, and you need a matching number of rows prepared for this table;
3. Some cell, where you can determine the row of 1st label sheet the addresses must start (i.e. to pass rows where labels are peeled off);
4. A report sheet, with table where 2 columns cells set to match label dimensions, and additional columns (and rows) to ensure the needed spacing between labels. Hard Page must be used to ensure only right number of label rows - it's 7 as I can see from your example workbook - is printed to every label sheet). This table must have enough rows for max number of marked labels even when on 1st label sheet printing starts from last row;
5. In Report Sheet, you use worksheet formulas to read From and To addresses starting from row you marked as starting one for 1st label sheet;
6. You have to define a dynamic Named Range, which includes all and only pages on Report Sheet, where are labels to print;
7. You define a Print Area for Report sheet, and set it equal to Named Range you defined.

It's all!