Webmin issues in Virtualmin

You're not after Usermin configuration--that's specifically for mailbox/ftp users--not Virtualmin created virtual server administrative users or reseller users, at all. Let me say that emphatically so no one is confused: Resellers don't even have a UNIX account, and can't even login to Usermin. At all. ;-)

Resellers cannot have (much) additional stuff at this time. They are intended for creating virtual servers, disabling them, backing them up, etc. but not for low-level administration of the virtual servers. And, the feature you describe doesn't exist in GPL, as the reseller account type doesn't exist in GPL. ;-)

But, you're probably actually just wanting to make a server, and then several sub-servers under it. All sub-servers are then managed by, and share group membership and permissions and ownership with, the parent virtual server. Of course, if you're actually creating an account that will manage other customer's accounts, then reseller is what you need...and you'll want to file an issue in the issue tracker to see about getting some additional flexibility in the reseller account type. We try to make things as simple as possible, but no simpler. Unfortunately, everything ends up being way too complicated...but we try to fight the complexification of things.