Scheduling by server time rather than local time?

When I set a block to appear at 17:00 it appears at 5 p.m. *local time* rather than 5 p.m. *server time*. I’d like a particular block to appear at 5 p.m. EST, as a promo for a daily video show that goes live at 6 p.m. EST.

I’ve tried this with both the Misc/Scheduling functionality, and this shortcode:

[ADINSERTER CHECK scheduling=”17:00:00, 20:00:0, 01234″]

Both approaches use local time, rather than server time.

Is it possible to set a block to appear at 5 p.m. *server time” rather than 5 p.m. *local time*? Either through some configuration within Ad Inserter Pro or through a function or update to wp-config? Thanks!