Ability to play a position without Kings

Hi,

I have a student and I'd like to play a mini-game with him - Rook vs 5 pawns. No Kings:

lichess.org/editor/8/1ppppp2/8/8/8/8/8/7R_w_-_-_0_1?color=white

Unfortunately, I can't play out such a position on lichess... Is there any way to make this work?

You would have to play under rules of a different variant (and choose which). Under standard chess rules such position would be an immediate draw at best. (Or rather wouldn't make any sense to play at all.)