DMI Drilldown 'Custom value' Regex?

Can the 'custom value' DMI Drilldown filter feature perform some kind of smart filtering, regex for example? I note we can do this now with conditional display of sections/fields etc.

https://community.dynatrace.com/community/display/...

Use case.

Customer has user defined sites laid out as follows. A customer site, is made up of more than one 'Client Site'.

Client Site = Site A - VoIP
Client Site = Site A - Data
Client Site = Site A - WiFi

Client Site = Site B - VoIP
Client Site = Site B - Data
Client Site = Site B - WiFi

etc.

(there is already a hierarchy of Client Region and Client Area already being fully utilised)

Customer would like to be able to drill down from a report showing all sites (sorted by affected users for example), into a report that shows ALL software services for the site.

e.g. on the Sites report, user clicks on Site A - VoIP, expected outcome is a report where the Client Site dimension is filtered: Site A - *

Allowing the user to see the performance of VoIP, LAN data, and WiFi data networks at a site.

So the conditional display system seems to say we could do something like

<Software service> ==~ '.*-' 

to return:

Site A - 

or

Site B - 

which as a filter would work for us.

Can this be done with a drill down?

I've tried like this:

<Software service> ==~ '.*-'

But trying to display that reports results in a 400 error from the CAS

Trying simply:

.*-

Doesn't work either (I didn't think it would), no error is shown instead it is treated literally as a text filter.