Two different google tag manager accounts in same domain

Question

I have two google tag manager accounts one mine and another of third party website and I need to put these 2 in this third party website. I tried put two gtm scripts after body

Answer 1

Updated information:

According to Google official document (https://developers.google.com/tag-manager/devguide?hl=en#multiple-containers)

It suggests:

1. For the best performance of a page, keep the number of Google Tag Manager containers on the page minimal.
2. If you use more than one container on a page, implement the container snippets with a common data layer object.
3. Using more than one data layer can cause some triggers to stop working and could have other implications. So don't rename the data layer for a subset of containers on the page.
4. You can, if necessary, rename the data layer for all containers on the page.
5. Avoid implementing a Google Tag Manager container through a custom HTML tag in another Google Tag Manager container

For more details and example refer to this official page link: https://developers.google.com/tag-manager/devguide?hl=en#multiple-containers