1. A computer-implemented method for providing multiple routes for multiple passenger groups, the method executed over a computer network, the method comprising: constructing, by a computer, an individual query for a first passenger group, the individual query having query attributes that are used to find travel solutions, the query attributes including values for origin, destination, number of travelers, date of departure, and time of departure; sending by the computer the individual query to a travel planning system; receiving, by the computer, solutions comprising sets of flights and fares usable with the flights from processing of the individual query; selecting, a single, individual solution from the solutions received by the computer from processing of the individual query; deriving, by the computer, constraints on values of at least one of the query attributes from the single individual solution to apply to a subsequent individual query for a subsequent, different passenger group; adding by the computer constraints to subsequent individual queries for the subsequent passenger group based on previously selected individual solutions and one or more of joint travel requirements and preferences with at least one of the joint travel requirements and preferences including sharing a common segment of travel; and constructing, by the computer, the subsequent individual query for the subsequent passenger group, the subsequent individual query for the subsequent passenger group having values for query attributes determined based at least in part on the constraints on the values derived from the single individual solution from the first passenger group.