Optimization on Many to Many to Many

Here's what you have to do.

1. Connect the ScenarioGroup table to Lane Masterdata as you have: ScenarioGroup[ScenarioGroup] 1 - * 'Lane Masterdata'[ScenarioGroup] where filtering is one-way from ScenarioGroup to 'Lane Masterdata'.

2. Connect Lane Masterdata to Bids: Lane Masterdata[LaneID] * - * Bids[LaneID] where filtering is one-way from 'Lane Masterdata' to Bids. Hide 'Lane Masterdata' (that's the best thing to do). You should only see ScenarioGroup and Bids. In ScenarioGroup you should only see the columns: Group, Scenario. In Bids you should only see: LSP. All other columns should be hidden.

3. Create 3 measures. In Bids create [Total BID]

Total BID = SUM( Bids[BID] )

In ScenarioGroup create [Minimum Total BID]

Minimum Total BID = 
var __shouldCalc =
    HASONEVALUE( ScenarioGroup[ScenarioGroup] )
var __result =
    if( __shouldCalc,
        MINX(
            ALLSELECTED( Bids[LSP] ),
            [Total BID]
        )
    )
return
    __result

and [Minimum LSP]

Minimum LSP = 
var __minTotalBid = [Minimum Total BID]
var __result =
    CONCATENATEX(
        FILTER(
            ALLSELECTED( Bids[LSP] ),
            [Total BID] = __minTotalBid
        ),
        Bids[LSP],
        ",",
        Bids[LSP],
        ASC
    )
return
    __result

Then, in your matrix, you can remove LSP from columns (leave the rest) and drop the measures in there. You'll see they do what you want. Also, you should have a slicer in the canvass for the LSP field. Play with it to see that the measures do indeed do what you wanted.

Best

D