We report on rotationally resolved IR spectra of dimers of HDO as a deuterium (d) donor with H2O, HDO, and D2O embedded in superfluid Helium nanodroplets in the 2650-2660 and 2725-2740 cm(-1) regions of the O-D donor stretch and symmetric acceptor stretch vibrations, respectively. By comparing spectra at different levels of deuteration we were able to unambiguously assign the donor stretch signals of H2O center dot center dot center dot DOH, HDO center dot center dot center dot DOH, and D2O center dot center dot center dot DOH. For H2O center dot center dot center dot DOH, three Delta K-a = 0 sub-bands were found that were assigned to transitions from the lower and upper acceptor switching states of K-a = 0 and the lower acceptor switching state of K-a = 1. In addition, b- and c-type transitions in the acceptor stretch region of HDO center dot center dot center dot DOH were observed that allowed us to determine the acceptor switching splitting of Delta(nu) over tilde = 5.68 cm(-1) in the HDO center dot center dot center dot DOH vibrational ground state. We suggest that the dominating broadening mechanism is intervibrational relaxation due to coupling of the rovibrational levels of the chromophore via internal droplet excitations.