Setting a random animation frame from multiple animations

Hey guys!

So I have a character and I want to set a random animation frame every time I press Space for example. I have 3 animations (anim1, anim2, anim3) of which each has 50 different poses. I'd also like to know how to set it to randomize from anim1 poses and if i'd have anim1 and anim3 enabled it would randomize a frame between those two. Note: when it sets a random frame it will be just in static state. not to play animation from a random frame

So the mechanics in words: anim1 activated push button = sets a random frame from anim1 (example frame: 27) push button = randomizes frame again (example frame:5) activate anim1 and anim3 push button = randomizes frame (example anim1/frame 22 or anim3/frame 14) and so on.

Thanks in advance!