Never mix benzodiazepines with alcohol, no matter the dose, and no matter the amount. Just a bad idea all around. If you are planning on having a drink or two, skip the Xanax. If you feel you need the Xanax, then skip the alcohol.
Also, just FYI, alcohol (especially when consumed to excess) will exacerbate anxiety something terribly. Anxiety and alcohol are a bad mix.
.25 Xanax is not heavy. But don't play around like that. You take a benzo you drop alcohol. it doesn't mean it's the last drink you'll have.
Call your pharmacist if they are open or perhaps a hospital will help if you phone them. I wouldn't touch alcohol on any meds because I don't see the purpose.