Split number in random parts with constrain

I am trying to find a smart way for splitting a number (eg 50) into a number of random parts (e.g. 20) BUT under the constrain that each generated random value cannot be greater than a specific value (e.g. 4).

So for example in this case I would expect as an output a vector of 20 values of which sum is 50 but none of the 20 values is greater than 4 (e.g 2.5, 1.3, 3.9 etc..)

I had a look at similar questions but from what i see these are dealing with splitting a number into equal or random parts but none of them included the constrain, which is the bit i am stuck with! Any help would be higly appreciated!!