My roster requirements are as follows

2 QB's- Start 1

4 RB's- Start 2

4 WR's- Start 2

Start 1 WR/RB

2 TE's- Start 1

2 K's- Start 1

2 D/ST- Start 1

I'm tying to strictly enforce this roster so somebody can't have 6 WR's 3 QB's etc. I want a balanced roster. How could I get this to happen. Everytime I try it on roster requirements, it gives me a warning and I can't figure it out. I don't know. I may be missing something completely obvious. Any help would be appreciated. Thank you