The conserved scalar or mixture fraction approach was originally derived for two-feed systems with one oxidizer stream and one fuel stream. Under the assumptions of unity Lewis number for all chemical species and sufficiently large values of the Damkohler number, it is known to provide a widely used and very efficient basis for the calculation of turbulent diffusion flames, which may be handled through the single knowledge of the mixture fraction statistics. The mixture fraction variable is also central to steady laminar flamelet representations, which provide a common building block to a variety of modelling proposals for turbulent combustion in nonpremixed and partially premixed situations. However, as soon as dilution by a third inlet stream comes into play, the corresponding formalisms, which rely on the mixture fraction concept, should be revisited. This restriction occurs, for instance, when an additional stream of oxygen-enriched air is introduced with the purpose of either achieving high temperature levels or favoring flame stabilization. Such a situation clearly exceeds the scope of the standard conserved scalar framework. The present study is aimed at extending the two-inlet mixture fraction basis to the consideration of such multiple-inlet injections. For this purpose, we introduce the notion of a fictive (or notional) injector, whose characteristics are reconstructed from the transport of either (i) inlet tracers or (ii) associated compositions of each inlet. The performance of the proposed approach is illustrated through its application to moderate and intense low-oxygen dilution (MILD) combustion of a jet in a hot coflow (JHC) burner. Comparisons performed between measurements and numerical simulations confirm that the proposed framework is able to render the third inlet influence, as well as the effects induced by variations of oxygen concentration in the hot coflowing stream. The proposed approach thus offers a simple way to extend the use of a wide variety of available turbulent combustion closures, which are based on the mixture fraction, to practical conditions featuring more than two feeding streams. (C) 2014 The Combustion Institute. Published by Elsevier Inc. All rights reserved.