AdvMemo region definition

I'm trying to create a rule for code folding. I have added RegionDefinition element with:

RegionStart = IF

RegionEnd = ENDIF

RegionType = rtClosed.

It's working fine with code like this:

But in my
language I need to use function if(condition, result_if_true, result_if_false).

And if this function is appears inside this region, then code folding starts from this if() function (not from "if" keyword)

I've tried to create additional RegionDefinition for this function with

RegionStart = if(
RegionType = rtIgnore (or rtOpen)

but with no success.

It's possible to define different RegionDefinition for block  if...endif and function if(...) independently?

Unfortunately, a special character like ( or [ can't be part of an identifier for a region. ( and [ are treated as symbol delimiters.