two antenna 'sectors' off one xr9 card?

I noticed the xr9 card has two mmcx ports on it and ROS has some options for antenna a and antenna b.

Can I cover two ‘sectors’ from one card? IE put one antenna on ‘a’ facing one direction and an antenna on ‘b’ facing another? If so how would this affect power to the antenna’s? (IE each antenna gets half of the roughly 28dbi the card is capable of?)

I believe these ports are usually for dual nstreme??? but thought this was worth asking as it has the potential to be a cost saver for me.

Short answer is no. You could use an external antenna splitter but I would really advise against it.