Voice Isolation in Audio

I need a skilled audio engineer to isolate two female voices from a 37-minute M4A audio file with significant background noise (male voices). The task involves removing two male voices while retaining the clarity of the female voices for personal listening.

Requirements:
- Experience with audio editing and voice isolation
- Proficiency in handling M4A files
- Ability to isolate a voice from other overpowering voices

Ideal Skills:
- Familiarity with audio editing software (e.g., Audacity, Adobe Audition)
- Attention to detail
- Good ear for audio quality

Please provide a sample of previous similar work and estimate the time required for completion.