Multiple-parties signature schemes please let me know if there's any digital signature scheme for the following problem. Thanks in advance!


I want to have a token that's somehow signed (or granted) by multiple
3rd parties for a certain document. The token then can be used to
access resources managed by the parties.  
3rd parties just need to use their private keys to validate the token


I find the Wiki article about Multisignature, but really I don't know how to apply it into my case.
Generate the token as a random number. Have each of the parties sign the token independently. Each will provide one signature on the token. Concatenate all the signatures into a big string. That string can then be sent when resources are requested. Each party can verify that its own signature exists in the string.