"Probably". Most residential-grade type equipment is designed to work with multiple (single-line) POTS lines from the telephone service provider.
Vonage provides a single-line POTS line, on the 'telephone' side of the 'adapter'.
Note, be sure to co-ordinate wih whomever is installing the Internet 'fractional' T-1, to arrange for an enhanced QOS, or at least priority, for the VOIP traffic on your T-1. Three simultaneous voice conversations can tie up 50% or more of that pipe. That's a big enough share that you don't want the risk of 'non-real-time' traffic pigging the bandwidth.