Constraint programming (CP) is an emergent software technology for declarative description and effective solving of large combinatorial problems especially in areas of integrated production planning. In that context, the CP can be considered as a well-suited framework for development of decision making software supporting smali and medium size enterprises in the course of Production Process Planning (PPP). The problem considered regards of finding of computationally effective approach aimed at scheduling of a new project subject to constraints imposed by a multi-project environment. In other words, we are looking for an answer whether a given production order specified by its cost and completion time can be accepted in a given manufacturing system specified by available production capability, i.e., the time-constrained resources availability. The problem belongs to a class of multi-mode case project scheduling problems, where the problem of finding a feasible solution is NP-complete. The aim of the paper is to present the CP modeling framework as well as to illustrate its application to decision making in the case of a new production order evaluation. So, the contribution emphasizes benefits derived from CP-based DSS and focuses on constraint satisfaction driven decision-making rather than on an optimal solution searching.