Yes.
Create a 2nd copy of you Thetis for HL2 folder.
Create a shortcut to Thetis.exe in each folder.
Customize the target to add the path to the database for each shortcut.
Here my files are in D:Data.
The complete paths I used are:
Target:
D:\Data\ThetisHL2-1\Thetis.exe -datapath:"%appdata%\OpenHPSDR\Thetis-HL2-x64-1
Start In:
D:\Data\ThetisHL2-1
Target:
D:\Data\ThetisHL2-1\Thetis.exe -datapath:"%appdata%\OpenHPSDR\Thetis-HL2-x64-2
Start In:
D:\Data\ThetisHL2-2

When you start a 2nd instance of Thetis you will see a warning that one is already running. That is OK.
Configure all your parameters. I give each Shortcut a name of my HL2 and I also configure the title bar so make it easy to identify each one.

The Title Bar Text can be customized in Setup – General-Option Tab

You can verify the 2 are separate databases by hitting the Export button and look at the folder it opens.

Note the correct folder, here for HL #2
