How multisig address may work.

ANYONE can find lists with similar interests. For example - https://memo.sv/posts/new?s=rape

In order to create multisig address you need public keys.
https://bitcointools.site/tool/address-to-pubkey
Only used addresses have public keys revealed (see my previous post).
...
Here are 4 IMO honest lists with public keys revealed:

1) https://memo.sv/post/de15da4e0a461a7136f996b3e335feddd8328d06d086f9a29c88b9417feb6ff8
address: 1JphZzE3mNhZervKK7FspCyJq9Mk5HKvco
public key: 02777e6860c204a6acb4b6f5e0bcceaf5595d8ad4a6929db1ca327b087f6d5bb55

2) https://memo.sv/post/44ebf1ec62374913ffc52a6c0df0b999d30a892f8d2ea6818c9ccc6ab4743222
address: 16uK3sX74ZHVVaBJqRSz44ZYanaQugDkRV
public key: 044fc267e4fa60878ddb07708e22295cbd1738e2835817dfac7df8e5e74b335a825340fa2dd04d7e65ecfdf96ea95a4a1afce8a83243fe25392f8567c902c4f397

3) https://memo.sv/post/32708829dc189758ca73e73fbecf907a79a6e871685746006441c49288a70314
address: 1BpzhusS2w28DVA7a1BM3Dw4HdwwXhs6sa
public key: 0417ab3338800325e561f964b03f26b4df49545dcba3fbbff7a8ab2cb20a5e8591af13d9f53ec21b412b738c0161c033cbd27daf597c051ef6c4b0aa79c7f39e3d

4) https://memo.sv/post/d2ed18d1f9992dbed43612826be3f59596985597466041315b16d7bfe69a721d
address: 13fSbf5RScS5dSC5SHXdUDY186qBaSW91o
public key: 0303fe245cff81a5a8d288ae6ee0f347d5453eff3024deaa55ddb75ff899f8beb4

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ANYONE can go to https://coinb.in/#newMultiSig and create 3-of-4 multisig address:
Address: 3JMZSKYegRxxLiYuT7xJerHpafyrQTcuGC
Redeem Script:
532102777e6860c204a6acb4b6f5e0bcceaf5595d8ad4a6929db1ca327b087f6d5bb5541044fc267e4fa60878ddb07708e22295cbd1738e2835817dfac7df8e5e74b335a825340fa2dd04d7e65ecfdf96ea95a4a1afce8a83243fe25392f8567c902c4f397410417ab3338800325e561f964b03f26b4df49545dcba3fbbff7a8ab2cb20a5e8591af13d9f53ec21b412b738c0161c033cbd27daf597c051ef6c4b0aa79c7f39e3d210303fe245cff81a5a8d288ae6ee0f347d5453eff3024deaa55ddb75ff899f8beb454ae

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And that's basically all done - ANYONE can use this address in any way.
Participants can top up it regularly, and potential agents will see it, and trust them together more than separately.

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And ANYONE can initiate multisig transaction:
open https://coinb.in/#newTransaction - paste the redeem script - and specify target address(es) and amount(s).

For example I topped up 0.0041 and created an unsigned transaction which sends 0.001 to all of 4 participants:
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

ANYONE can verify it here https://coinb.in/#verify

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And now, any 3 of participants can sign it one by one:
- sign https://coinb.in/#sign
- and publish hex string here

And the third signer can broadcast it https://coinb.in/#broadcast

(Signing order is not important - see https://blog.coinb.in/guides )

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Notes:

- The only big problem with coinb.in is calculating transaction fee. I am not sure how to do it and just added +0.0001 without calculations.
(Unsigned tx is 390 bytes long, 0.0001 is 10000 satoshi, 10000/390=25 sat/byte - it should work.)

- For better safety you should disconnect internet when signing tx with your private key. Coinb.in is a famous mature project, but you can't be too careful.

- In BTC it's impossible to add-remove co-signers, but in NEM and Gnosis it is possible.