Greg, thank for advise.
But I don't know how I can take current row ID in t1.
I used such expression:
xdXDocument:GetDOM("v1")/dfs:myFields/dfs:dataFields/d:v1/@Value[../@ID
= xdXDocument:get-DOM()/dfs:myFields/dfs:dataFields/d:t1/@ID]
But this expression box displays value from v1 that matches with first ID in t1 for ...