Tags to differentiate multiple email accounts

I have 2 emails under my APWT account,
one for general contact (Email 1) while the other is for contacting specifically about a product (Email 2)

I want to be able to
1) Sort through my emails so I can prioritize the emails regarding the product first especially on my dashboard
2) I want to be able to see which email the clients are replying to right from my dashboard with some sort of color code or visual cue

My suggestion would be to create a tag option for custom fields under contacts of clients that reply either email (in this case, a tag for people who respond or are contacted by Email 1 and another separate one for Email 2)
OR
Have an option to add a tag to different emails that are registered under my APWT account