Multiple Secondary Models as Primary Engine using Back to back

I have 3 questions:

Q1) Is it possible to have 4 different models used within back to back all as primary engines?

Q2) Is it possible to have 2 primary models and multiple secondary models?

Q3) I have noticed there are multiple instances of deepstream within a deepstream app. Can someone point me to the appropriate source?

Q1) Is it possible to have 4 different models used within back to back all as primary engines?

-> yes, it’s possible to run with all nvinfer set to primary mode.

Q2) Is it possible to have 2 primary models and multiple secondary models?

-> yes, possible.

Q3) I have noticed there are multiple instances of deepstream within a deepstream app. Can someone point me to the appropriate source?

-> multiple instance of deepstream within deepstream-app, do not quite understand what you mean.

Thank you!