  We generalise the procedure for joint estimation of cosmological parameters
to allow freedom in the relative weights of various probes. This is done by
including in the joint Likelihood function a set of 'Hyper-Parameters', which
are dealt with using Bayesian considerations. The resulting algorithm is simple
to implement. We illustrate the method by estimating the Hubble constant H_0
from the recent Cosmic Microwave Background experiments Boomerang and Maxima.
For an assumed flat Lambda-CDM model with fixed parameters (n=1, Omega_m =
1-lambda = 0.3, Omega_b h^2 = 0.03, Qrms = 18 mu K) we solve for a single
parameter, H_0= 79 +- 4 km/sec/Mpc (95 % CL, random errors only), slightly
higher but still consistent with recent results from Cepheids. We discuss how
the 'Hyper-Parameters' approach can be generalised for a combination of cosmic
probes, and for other priors on the Hyper-Parameters.
