Email list in T-SQL

I have a sql task in a ssis package loops through each customer and emails a file. So for every iterateion I need to create a list of To Recipients, CC, and BCC with the semicolon between the addresses. I was trying a case statement but I do not know if that will work?

So For Every ONE Customer, I want to create one TO, CC, and BCC Columns which gets passed to a pckage variable - then used when sending email.

SELECT  HDR.CUST_NUM,
       HDR.CUST_NAME,
       HDR.CNTC,
       DTL.EM_TYP,
       CASE 
           WHEN EM_TYP = 'TO' THEN dtl.EM_ADDRESS 
           WHEN EM_TYP = 'CC' THEN dtl.EM_ADDRESS 
           WHEN EM_TYP = 'BCC' THEN dtl.EM_ADDRESS 
       END AS [TO_RECIPIENTS]
FROM DEV_USR.dbo.T_WKLY_DIST_HDR hdr
JOIN DEV_USR.dbo.T_WKLY_RPT_DIST dtl
ON dtl.CUST_NUM = hdr.CUST_NUM
GROUP BY    
HDR.CUST_NUM,
       HDR.CUST_NAME,
       HDR.CNTC,
       DTL.EM_TYP,
       DTL.EM_ADDRESS

result for [To] would be something like = me@mycompany.com; you@mycompany.com ; us@mycompany.com - so that it emails one time properly