Generalise spread around the control to spread around any member

### What problem does your feature request solve?

It is possible to consider the spread around a specific member, whilst traditionally it would be the control. In thoery any member could be used.

### Describe the solution you'd like

Expansion of the operator produced in #1661 and a new recipe.

### Describe alternatives you've considered

Start by reading the operator introduced in issue #1661 and locating the existing spread-around-control implementation and recipes. Determine how the operator currently identifies the control, then define the generalised behavior and add a recipe showing spread around another member; done means both the operator and recipe support that use case.

Written by the indexing model from the issue text.