Choose a user every time start a workflow

Hi everyone,

I have created a workflow in aem6.3  and assigned a group to it. So it will works like every time i choose to start this workflow and the whole group will get notification about it.

And my question is how can i choose a member using like a drop-down list? The drop-down list contains only all the members in the group. So i can choose what i want every time starts a workflow. Is there any OOTB way for this?

Thanks for your time and help.