Illumra ZBT-S1AWH Wireless ZigBee Switch

This is the same thing as grouping lights. For dimming you would have to use one of the custom SmartApps. Trendsetter or one of the newer dim and dimmer variations could probably do it. You can find these by using the quick browse list in the community – created wiki and look for lighting in the smart app section.

http://thingsthataresmart.wiki/index.php?title=How_to_Quick_Browse_the_Community-Created_SmartApps_Forum_Section

Or you could jump right to core. But none of these would run locally, if that’s an issue, as custom code doesn’t run locally at the present time. Only smart lights can run locally right now.

All of that said, three seconds seems like a long time. When did you last run A zwave repair?

https://support.smartthings.com/hc/en-us/articles/200981864-How-do-I-make-sure-my-Z-Wave-devices-are-routing-optimally-