Thanks for reaching out to Adobe Community.
You may want to look at the below article which explains on how to setup mbox rules within DTM.
for third part tags see: https://marketing.adobe.com/resources/help/en_US/dtm/t_third_party_tags.html
Thanks for the reply, but I am looking for firing 3rd party tags as part of Target Offer code. So that I can control for how many visitors to fire/control the tags.
Thank you for reverting on this.
In VEC you can use the “</>” menu item to insert any kind of code right after the body tag. So, technically you can do it. But depending on the complexity of the js tags, there may be side effects, and you need to test it thoroughly.