Formatting Block to indent relative to where its parent would be

Hello,

I'm trying to perform auto-indent using a FormattingModelBuilder in my custom language. However, it's indenting the way, I would want it to, and I can't figure how to get it right.

This is what I would like:

<indentTest> =
(
    one | two
    | three (
        four five
    )
    | six
);

but this is what I get:

<indentTest> =
(
    one | two
    | three (
    four five
)
    | six
);

Note that it works as expected, if the first parenthesis of the group start on a new line:

<indentTest> =
(
    one | two
    | three
    (                    <----
        four five
    )
    | six
);

I have the Block structure arranged so that each word token or "|" symbol is a LeafBlock, and each "(...)" is a GroupBlock which has child which are each LeafBlocks or GroupBlocks. All the children of a GroupBlock have Indent: NORMAL except for the blocks for the parentheses characters themselves which have Indent: NONE.

I understand that this is because the indentation of a given block is relative to the closest ancestor Block which starts on a new line. In the above case, since the parent GroupBlock of "four" does not begin on a new line (it comes after "three" on the same line), the "four" block is indented relative to the outer GroupBlock which is aligned with the leftmost column.

How could I change my Block structure or Indentation assignment to make this work as I would like? I want the entire Group to be indented relative to the line on the which the Group starts. I've tried to get this to work with Alignment, but while I could finagle the closing ')' to align in the right place, that still doesn't help with the indentation of inner elements of the GroupBlocks.

Thank you!