Dear Biojl,

currently there is no way to directly get the cds sequences from all the proteins in an OMA group or HOG from the web interface. However, there is a way how you can get them with quite little programmatic effort from the REST API. Here's a possible way how you could get them in python and output them as fasta:

import request, json
grp = 12345
group = json.loads(requests.get('https://omabrowser.org/api/group/{}/'.format(1345)).content.decode())
group_members_entries = [p['omaid'] for p in group['members']]

reply = requests.post('https://omabrowser.org/api/protein/bulk_retrieve/', json={"ids":group_member_entries})
group_members = json.loads(reply).content.decode())
for memb in group_members:
    print(">{}\n{}\n\n".format(memb['omaid'], memb['cdna']))

We also see that this might be generally a useful feature and will therefore implement it for the next release.