A measurement is presented of dijet and 3-jet cross sections in low-\t\ dif
fractive deep-inelastic scattering interactions of the type ep --> eXY, whe
re the system X is separated by a large rapidity gap from a low-mass baryon
ic system Y. Data taken with the H1 detector at HERA, corresponding to an i
ntegrated luminosity of 18.0 pb(-1), are used to measure hadron level singl
e and double differential cross sections for 4 < Q(2) < 80 GeV2, z(p) < 0.0
5 and pT,(jet) > 4 GeV. The energy flow not attributed to jets is also inve
stigated. The measurements are consistent with a factorising diffractive ex
change with trajectory intercept close to 1.2 and tightly; constrain the do
minating diffractive gluon distribution. Viewed in terms of the diffractive
scattering of partonic fluctuations of the photon, the data require the do
minance of q (q) over barq over q (q) over bar states. Soft colour neutrali
sation models in their present form cannot simultaneously reproduce the sha
pes and the normalisations of the differential cross sections. Models based
on 2-gluon exchange are able to reproduce the shapes of the cross sections
at low x(p) values.