  We determine the atomic hydrogen (HI) to halo mass relation (HIHM) using
Arecibo Legacy Fast ALFA survey HI data at the location of optically selected
groups from the Galaxy and Mass Assembly (GAMA) survey. We make direct HI
detections for 37 GAMA groups. Using HI group spectral stacking of 345 groups,
we study the group HI content as function of halo mass across a halo mass range
of $10^{11} - 10^{14.7}\text{ M}_\odot$. We also correct our results for
Eddington bias. We find that the group HI mass generally rises as a function of
halo mass from $1.3\%$ of the halo mass at $10^{11.6} \text{M}_\odot$ to
$0.4\%$ at $10^{13.7} \text{M}_\odot$ with some indication of flattening
towards the high-mass end. Despite the differences in optical survey limits,
group catalogues, and halo mass estimation methods, our results are consistent
with previous group HI-stacking studies. Our results are also consistent with
mock observations from SHARK and IllustrisTNG.
