You do not need to be in the same room to get a matching look. We recommend a Distributed Measurement Protocol:

• Video Guides: Groomsmen can measure themselves at home using detailed video tutorials.
• Courtesy Measures: Remote groomsmen can visit a local alteration tailor in their city for a professional measurement (often for a small fee) and submit those numbers.
• Clone Fit: If they own a suit that fits perfectly, they can measure the garment itself rather than their body for high accuracy.