Formal group letter (from multiple people to one recipient)

Location: Poland / European Union Me and my friends are trying to write a formal letter (on paper) to bunch of EU officials regarding a certain legislation (its a lot of letters when multiplied per senders and receipients so to save money, we sign together on one letter, and each letter like this goes to different official) We are trying to voice our opinion as a group of people who know eachother- not a petition where someone walks in a city and collect signatures from random people who might not be well informed on a topic.

If its 10+ people with different adresses, do we all need to put our own sender blocks? Do my friends need to even put their own adress? Its suprisingly hard to find info on this and chatgpt seems to agree to every variation and idea how to structure this, this doesnt seem confident...

My current approach is (ignore periods, i use them for reddit post formatting)

[Sender Block - my adress]

(Date, place of signing connected/under to sender block)

.. ..

[recipient block with their formal adress and tittle]

.. ..

(Body with formal salutation ect...)

..

Sincerely,

On behalf of all undersigned:

{Idk if reddit wont mess up formatting on this post but its basically a text table}

..

Print Name . . . Adress . . . . Signature

Me . . . . my adress . . . . my signature

Friend1 . . . . their adress . . . . their signature

Friend2...