Slicer priority

You can use concatenatex to return a sequence of values as a scalar string.

Concatenatex( values( slicer[region] ), slicer[region], "-", slicer[Region], asc)

This will order the resulted based on a expression in the case above region alphabetically ascending, but can be customized.

There is no way for this to know what order you selected the values in the slicer though, which is sounds like you what you wanted to achieve

Hi fabconmvp 

Deku 's suggestion is the only possible way. Power BI does not retain the order in which slicer items are selected. The results follow either the order defined in the data model or are sorted alphabetically in ascending or descending order.

Hi fabconmvp,

May I ask if you have resolved this issue? If so, please mark it as the solution. This will be helpful for other community members who have similar problems to solve it faster.

Thank you.

Hi fabconmvp,
I wanted to check if you had the opportunity to review the information provided. Please feel free to contact us if you have any further questions. If my response has addressed your query, please accept it as a solution and give a 'Kudos' so other members can easily find it.
Thank you.

Hello fabconmvp ,

Could you please confirm if your query have been resolved? If they have, kindly mark the helpful response and accept it as the solution. This will assist other community members in resolving similar issues more efficiently.

Thank you.