Background Reciprocity for 1811

This is a post I entered on the 1811 sub, but was advised to post here as well.

Exercising the search function, I’ve seen people discuss background reciprocity for FED LEOs entering other agencies.

What about reciprocity for applicants who are still processing, but have passed their BI?

For an example, if you are further along with DEA and passed a BI, but coming up on needing to do one with ATF, is there reciprocity with your DEA approval where you do not need to do the process again with ATF?

Any help would be appreciated, thanks!

Also, if it helps, the whole “DEA and ATF” example, is my situation. If someone has specific information on that, it would be appreciated. Thanks!