How to make decisions within networks of groups?

Hey, iam looking for methods on decisionmaking (basically reaching consensus) within networks of groups and individuals. At best those methods would keep in mind that on face to face meetings not always all groups are present, or only sent delegates that eventually first need to talk back to their groups before being able to have a final stance on a decision that needs to be made.

How did anarchists implement that, what are processes on reaching consensus within anarchist unions?

The best would be a formalized 'algorithm' from proposing something to finally deciding something (with iterations and finding compromises).