Select all cameras facing towards line defined by 2 markers

[lieti]

Hi,
for archaeological processing of section profile I want to automatically select all cameras in the chunk which are facing towards line (axis of section) defined by 2 mark. With some deviation (e.g. +/- 10 degree). Example is in attachement

But I´m bit lost in yaw, pitch, roll and rototranslation issues.

Could somebody help me with hint, or example of code for this task?

Thanks in advance