Splitting my data

so basically i have a very large set of data and it is basically a list of results. for example if a random number generator was to continually choose a number between 1-5 I have the list of results looking like this:
row1: 4,4,1,2,1,5,4,3,2,1,4,3,2,4,1
row2: 5,2,1,5,3,1,5,1,3,4,2,1,4,2,2
etc.

In my case only one outcome value is important to me (lets say "3") and even more important is the length between each occuring and i want to change it to look like this:
row1: 4,4,1,2,1,5,4,3
row2: 2,1,4,3
row3: 2,4,1,5,2,1,5,3
row4: 1,5,1,3
row5: 4,2,1,4,2,2
etc.

i currently have the cells of value to me highlighted so it sticks out but that's just not going to cut it and would take me waaaaay too long to reformat this information manually. I do not want to change the order, I only want it to put everything on the next column everytime said cell appears. please can anyone help me to figure this out.