I've done it on 2,000 hp medium voltage (4160 VAC) blowers. We went a step further, and had synchronous transfer. After one blower was up to speed it synchronized with line voltage and switched the running blower to across the line operation. The VFD was then available for starting and controlling a second blower.
This is a standard system from many manufacturers. The one I did used Toshiba, but Allen Bradley and ABB have it too. You can buy the package with or without synchronous transfer.
Having said that, nowadays it probably isn't worth screwing around trying to use one VFD. By the time you get done with the interlocked contactors. engineering, disconnects and so on it is probably more cost effective to buy two VFDs. The system I did was quite a few years ago, when medium voltage VFDs were very expensive. At today's prices, for low or medium voltage and for most hp ranges VFDs are pretty economical.