SQL SERVER - FOR XML PATH

EXPERTS,

I have a stored procedure that I need to return data in a concatenated string format like this:

Reg~Dist~Clus!Reg~Dist~Clus!Reg~Dist~Clus&Reg~Dist~Clus!

In this example I have 3 UserIDS, the first 2 have only ONE Region,District,Cluster combination but the last one has 2 combinations.

I need to use FOR XML PATH to product this display.

RDC
000~002~351!000~037~309!000~003~124&000~003~148!


The "&" sign needs to be used to separate Reg,Dist,Clus combos within the same USER_ID.

This is what my source table looks like:

USER_ID      REGION      DISTRICT CLUSTER
253020      000      002      351
253254      000      037      309
253339      000      003      124
253339      000      003      148

This is my current "FOR XML PATH" SQL:

--FINAL DISPLAY
; WITH CTE_RDC_DISPLAY AS
(
SELECT
(SELECT REGION+'~'+DISTRICT+'~'+CLUSTER+'!'
FROM #TEMP
  --GROUP BY USER_ID,REGION,DISTRICT,CLUSTER
        FOR XML PATH('')) RDC

)
SELECT RDC
FROM CTE_RDC_DISPLAY


This SQL currently produces THIS:

RDC
000~002~351!000~037~309!000~003~124!000~003~148!


I need to have the XML modified to return THIS:

RDC
000~002~351!000~037~309!000~003~124&000~003~148!


The reason is that the last 2 RDC combinations belong to the SAME USER_ID.

Thanks.