How to treat specific water molecules as ligand?

Thank you Justin, would it be possible if you can show me an example for the “three constraints” for “position restraint”? Is it the same for “position restraint” and “flat-bottom restraint” (earlier thread)?

[ constraints ]
; ai aj funct length_A length_B
1 2 1 0.09572
1 3 1 0.09572
2 3 1 0.15139