Sticky key for profile swapping

Hi,
I don't seem to find any answer to my question, so I'll it ask here :
I use a key holding to change profile,
I press my key and once on the 2nd profile (key still down), I would like to recover my key (read by the 2nd profile).
Like I hold key 16 on the first profile to go on the 2nd one. Once on the 2nd profile, key 16 is Alt and key 17 is tab. So I just hold key 16 (to change profile and press Alt) and press key 17 as much as i want to navigate with my windows.

Thanks,

Peter