Am I davening as a Yachid or not?

Question

As per this statement, "If there's minyan of ten people and one person is praying a lengthy silent Shemona Esheh, it's preferable to wait for him, however, if there are needs such as if the minyan will separate or if it's a bother to congregation to wait, they may begin Chazarat HaShatz even though one is still saying Shemona Esreh" a minyan still seems to be a cohesive and singular unit even if everyone is not saying the same thing.

In my siddur, the Vidui said each morning has a section which, it says, is only said with a minyan, and a section which one could sing as an individual.

If I am davening with a minyan, but that minyan does not have the tradition of saying vidui every day, am I davening in a minyan (so I can say it) or as a yachid, since the rest of the minyan didn't say it (so I can't)?

And if I am in a minyan that DOES say it, but I have fallen behind because I daven Shmoneh Esreh slower, when I get around to it and the minyan is already elsewhere, am I still "part of a minyan that says it" or am I not part of the minyan so I should not say it?

Answer 1

This article explains that one may not recite the 13 Middot section of vidduy or Selichot (it has the same format) as a prayer form unless one is saying it together with the minyan saying it at the same time. If one wants to say it alone, meaning whether one is in shul while the cong. is saying something else, or one is at home outside the shul, one must read the 13 middot with the trope because it is considered as if one is studying Torah by doing it this way.

B"N, I'll try to extract the exact citation and edit it, here, when I can access that site.