SRTT variant with 1 or more simultaneous key responses

Hello all, 

I want to use an SRTT variant with optional 1 or 2 keys to be pressed simultaneously.
I was wondering 
a) whether this is at all possible to implement with PsyToolkit?
b) what the most reliable option would be for stimulus presentation and readout of response times, status?

I suspect that this has been done before but I could not find any related information in this forum or the online manual. 

Thanks a lot for your support. 
kirstin