Recommendation for student music ensemble?

Hello,

I'm organizing a staff appreciation event for the non-profit I work at and am looking for a small ensemble (up to four people?) to perform. Last year, we had a jazz trio and something similar would be great, though I'm open to suggestions of all all genres and instrumentation (including a cappella groups!), particularly for college-level or advanced high school-level musicians. This would be a paying gig. Please forward any suggestions of specific people or groups you might have to me. I've reached out to the music departments of local schools and haven't had much luck with responsiveness. Thanks so much!