Whatever happens you have to discuss the issue with them.
1) I think it is reasonable to tell them that appointing someone to take on all this responsibility without first discussing it with you and the others appointed is a little unreasonable, if not illegal, as they do not know whether those people would be able or willing to take on the work.
2) point out that they need to obtain consent from the attorneys, who have to fill in a form and sign it and none of you have received copies of this form.
3)Ask them whether the attorneys have been appointed to act severally or jointly (I will bet a penny to a pound they will not know what you are talking about), but it is important.
If you appoint attorneys severally, it means that one attorney can act as a representative of them all. My sister and I were attorneys for an uncle. When we had to invoke the POA, we agreed I would be the main carer, make decisions, write cheques etc and she would just be back up. If either of us had died, the POA would still be valid as one of us could act on their own.
If you appoint attorney's jointly, all the attorneys have to agree on everything, all have to counter sign cheques and if one dies the POA dies with them. A friend got caught by this. Her father appointed his daughter and her husband as joint attorneys. It never occurred to him that his SiL would predecease him. This caused no end of problems because the death of one of the attorneys meant that the POA was no longer legal. And, as her father by then, had severe dementia, she had to go through the Court of Protection to get POA, a problem she could well have done without.
I can see no alternative to speaking to them directly and I think asking for more details of the POA, when you will receive the form you must complete, how the attorneys will work etc, as described above, is the way to go about it - and if they cannot answer these questions i would kindly, but firmly tell them that you cannot consent to being an attorney.
If you know who the other putative attorneys are and can check whether they are aware of what has been done in their name and whether they are willing, you could all refuse to act until properly consulted, given the forms and had time to consider the issue.