Reuse same agents in call center queue

[Huan]

I want to create a ringgroup-ish call center queue to with delay. How do I reuse agents in the call center queue? Like call agent 1 after some time call agent 1 and agent 2.
In call center queue I set Tier Rule Wait Second to 1. It still take some time to go to the next tier level.

 

[Huan]

I managed to fake the "delay" in call center queue by using strategy Ring all, 2 levels and Tier Rule Wait Second to 10 seconds. The agent in level 0 has a timeout of 20 sec. The agent in level 1 has a timeout of 10 sec. First level 0 will ring. After 10 seconds the next level starts while the previous still rings.