When you sync leads to Salesforce or use a "change owner" flowstep, you can assign the lead to a queue in Salesforce. An SFDC queue can contain multiple members (users) that work on a shared pool of leads/cases/etc.:
In Salesforce I believe you can configure notifications so that all queue member are emailed when a new lead is assigned. From there any member of the queue could pick up the lead and change ownership to themselves.
You can't, however, assign tasks to queues as far as I know.