fnDynamicSelectList.pq

(l as list, selections as list)=>
let
    Source = 
    List.Accumulate(
        selections,
        {}, 
        (state,current)=> 
        if 
            Text.Contains(current,":") 
        then 
            List.Combine({state,
            List.Range(
                l, 
                List.PositionOf(l,
                    Text.Split(

                            current
                            ,":"
                    ){0}
                ),                List.PositionOf(l,
                    Text.Split(

                            current
                            ,":"
                    ){1}
                ) - List.PositionOf(l,
                    Text.Split(

                            current
                            ,":"
                    ){0}
                )+1
            )}) else List.Combine({state,{List.Select(l, each _ = current){0}}})
    )
in
    Source