HF, VHF or UHF?
If narrowing your roofing filter — and tightening your passband filter — is not enough, you can try using PBS (pass band shift) and the notch on the offending edge to block some of it. But the rude reality is, if by function of pure wattage, sloppy audio or physical proximity that doesn’t work, you are probably down to negotiating with the perpetrator.
A directional antenna with effective nulls can also help, but it’s a BandAid at best.