Applying Macro To Entire Spreadsheet At Once

For simplicity, let's assume I have three columns, "Company," "Policy," and "Balance."

Example:
Company A Life $1
Company A Med $2
Company A Dent $3
Company A Disab $4
Company B Life $9
Company B Med $5
Company B Dent $7
Company B Disab $2

According to my post preview, the columns are running together, but I do have it arranged in three distinct columns. What I want to do is program a macro to do the following:

Every time the name of the company changes, I want Excel to insert two rows after the last of the group, and have a summation of the "Balance" column in the first inserted row.

This is what it should look like:

Company A Life $1
Company A Med $2
Company A Dent $3
Company A Disab $4
$10 <- (this should be directly under the $4, but I'm not good with forum languages)

Company B Life $9
Company B Med $5
Company B Dent $7
Company B Disab $2
$23 <- (same with this - should be directly under the $4)