  We present the wavelength-resolved reverberation mapping (RM) of combined
MgII and UV FeII broad-line emissions for two intermediate redshifts
(z$\sim$1), luminous quasars - HE 0413-4031 and HE 0435-4312, monitored by the
SALT and 1-m class telescopes between 2012-2022. Through this technique, we aim
to disentangle the Mg II and FeII emission regions and to build a
radius-luminosity relation for UV FeII emission, which has so far remained
unconstrained. Several methodologies have been applied to constrain the time
delays for total MgII and FeII emissions. In addition, this technique is
performed to quantify the inflow or outflow of broad-line region gas around the
supermassive black hole and to disentangle the emission/emitting regions from
lines produced in proximity to each other. The mean total FeII time delay is
nearly equal to the mean total Mg II time delay for HE 0435-4312 suggesting a
co-spatiality of their emissions. However, in HE 0413-4031, the mean FeII time
delay is found to be longer than the mean MgII time delay, suggesting that FeII
is produced at longer distances from the black hole. The UV Fe II R-L relation
is updated with these two quasars and compared with the optical FeII relation,
which suggests that the optical FeII region is located further than the UV FeII
by a factor of 1.7-1.9 i.e. $R_{\rm FeII-opt}\sim(1.7-1.9)R_{\rm FeII-UV}$. We
detected a weak pattern in the time delay vs. wavelength relation, suggesting
that the MgII broad-line originates a bit closer to the SMBH than the UV FeII,
however, the difference is not very significant. Comparison of MgII, UV, and
optical FeII R-L relations suggests that the difference may be larger for
lower-luminosity sources, possibly with the MgII emission originating further
from the SMBH. In the future, more RM data will be acquired to put better
constraints on these trends, in particular the UV FeII R-L relation.

Astrophysics of Galaxies;Cosmology and Nongalactic Astrophysics;General Relativity and Quantum Cosmology