You should see below samples as workarounds as VisualCron have no built in global queue.
Let say you have 3 Jobs that you want to sync globally. There are different alternatives for this.
1. Create 3 Conditions. Each Condition checks if one of the 3 Jobs are running. Select the Condtions that checks the two other Jobs in each Job.
About the loops. I don't know how often you want to run your Jobs but it is better to configure the Jobs to run more often so you don't have to create internal loops in the Conditions. But if you really want to create a wait loop in Conditions you have to be aware that these Conditions will lie in the background, checking these Conditions, at the Wait interval. This activity is in the background and will be hidden for you unless you add extra logging (Log tab of Condition).
2. The complete other way is easier. You just make sure that you only start one at a time. Many users use the VisualCron Trigger. This way you can create a chain of Jobs - so that one Job starts when the other has completed. I recommend this alternative if it works for you.