Set value to parsed JSON fragment from another file

[ilog2000]

Is it possible to extend functionality with setting value from another JSON file (parsed of course)?

I tried on Windows something like this

jj -i fragment.json -o temp.json -u
set /p fragment=<temp.json
jj -i source.json -v %fragment% Address

but it inserts a string value instead of JSON object. I believe on Linux I could use $1 to pipe argument, unfortunately, Widows pipes are very limited.