I've kept seeing it being done on other servers, so technically it might be possible to do but I don't know?
(Wish it was here)
One can make it look like a same sex marriage anyways by making another toon with a name as close as possible to the original, of the opposite gender, and just cross-marrying those to make the title appear as if it was one.
Idk it's the only method I know that can be done by yourself