How to create TimeZone relative to something else than UTC/GMT in java

I need to create a timeZone which is a fix offset to America/New_York

I would like to do something like that (DateTime lib): DateTimeZone MyTimeZone = DateTimeZone.forID("America/New_York+17");

But it is not possible.

The only thing i can do - is to get current offset to UTC/GMT and shift it by my additional offset.

DateTimeZone.forOffsetMillis(NYTimeZone.getOffset(time)+dt)

But this is not efficient - because i need to know the current time to know the current offset.

Thanks