Detect IF Agent Available As a Workflow Step

It would be very helpful to know if an agent is available before proceeding with a call flow step. For example if Agent "Sue" is the only one in a Team, I don't want to waste a customer's time ringing her for 30 seconds knowing that there will be no answer. I should be able to see that no agent is Online and proceed with a different workflow step, like ringing Agent "Bill", or going to another Menu.