realmd and a cross-forest trusting ad

Anyone tried a configuration of cross-forest trusting active directory domains and realmd?

I would need to enable authentication using account and group information from the main domain in question for the joined domain and another trusted domain.

Additionally I'm interested if a local group defined on the primary domain of the AD that includes users of primary and a trusted domain is usable as an authentication group for the host?

Any luck in this config or is it just something that is better supported by IPA and not by realmd?