VLAN Tagging / Trunking between PowerConnect 6224F and Cisco SG 300 Small Business Model

Hello,

I recently was hired to take over an IT department and one of my projects is upgrading the network hardware. Already in place as a core switch is a Dell PowerConnect 6224F with VLANs in place. The campus is set up with different buildings connected via fiber back to the 6224F. Each building is a part of its own VLAN and the servers are connected to a "General" link, where every VLAN port is set to "Access" and un-tagged in the associated VLAN.

There are routes for VLAN communication in the 6224F and also our Cisco ASA5505, while a Cisco 1841 handles DHCP for each of the VLANs.

It works great to have each building separated on its own VLAN but I am starting to upgrade the buildings from Netgear Layer 2 switches to Cisco SG300-52 Gigabit switches. We have a few cases where there is server or system in a different building and I want to tag it to the appropriate VLAN for the other servers.

I have played with a combination of Trunk settings on both the 6224F and the Cisco SG300 with no avail - its simple to have the whole fiber port on the 6224F to a certain VLAN and have it acquire the appropriate DHCP address but I cannot seem to tag the individual ports to different VLANs.

Has anyone had any success with this? Any tips or leads?

I appreciate any help in advanced!