On combining prayers

Salam alaikum,
There is another post in this forum where a brother is asking about the permissibility of combining prayers (dhuhr/asr and maghrib/isha) and the response was that it is permissible under 3 conditions:

1) Sickness
2) Fear
3) Preoccupation with religious/Godly activities (e.g. attending a religious lecture)

However, I remember reading (or watching a video) that there is a fourth condition, which is preoccupation with permissible activities (the example given was farming, but this would apply to work/school as well).

I thought that I read this in the Beneficial Summary, but I could not find it. I also could not find it in the video playlist about the Beneficial Summary on your youtube channel. So my question is, am I remembering correctly that you can combine prayers if you are preoccupied with permissible (not necessarily religious) activities? And where might these conditions be written?

Thank you
 

Thank you,

I have two more small questions.

1. Is there a translation of Al-Azhar, or some other English fiqh work that is more comprehensive than the Beneficial Summary?

2. In Masaa'll Al Qasim, the following is stated:

"He was asked: Can a woman drink some type of medication to prevent conception? Can a man make his bondswoman drink it to prevent conception? Can a man drink something to curb his desire?

He replied: None of this is permitted."

Does this mean that birth control pills are not permissible according to the Zaydi madhab?

I also wanted to thank you for your work in answering questions on this forum and translating important Zaydi works to English. I come from an Imami family but alhamdulilah I now follow the Zaydiyyah and inshallah I will raise my children as Zaydi in the future. This would not have been possible without your work.

Thank you again