VPN + direct internet access at same time?

I have few routers at distant locations working as hotspots and VPN clients connecting to my VPN server (PPTP). I’m using VPN only so I could access routers (I didn’t find any other way to connect over LTE, no public IP).

Now all traffic from hotspot goes trough my VPN server as expected, but it slows down surfing as number of routers grows.

Is it possible to configure router that WinBox port 8291 is connecting trough VPN and all other traffic uses local ISP?
Only connection to internet is via LTE USB modem.

Yes it should be possible to do that using a combination of “packet marking” for that TCP port and “IP Route rule”.