More logical links on a serial link between Cisco routers

I have got the question if there is any possibility to logically split the serial link between Cisco routers. Similarly to VLANs on Ethernet link. You can see the physical and logical view on image below:

Cisco supports these encapsulations on serial interface: Cisco HDLC, PPP and Frame Relay. As Cisco HDLC and PPP doesn't support such feature, Frame Relay is the only option.
First, you need to define the type of encapsulation of the serial interface:

interface Serial0/0/0
 no ip address
 encapsulation frame-relay

To create more logical interfaces you need to create more subinterfaces of the serial interface. For each subinterface you need to define its IP address and assign unique DLCI:

interface Serial0/0/0.50 point-to-point
 ip address 1.1.1.1 255.255.255.252
 frame-relay interface-dlci 50
!
interface Serial0/0/0.52 point-to-point
 ip address 2.2.2.1 255.255.255.252
 frame-relay interface-dlci 52

Usually there is a FR switch or DCE device between FR routers to provide Local Management Interface (LMI) status messages. As we have no such FR switch in our scenario we need to disable processing of LMI messages.

interface Serial0/0/0
 no keepalive

 The final configurations of both routers will be:

ROUTER1

interface Serial0/0/0
 no ip address
 encapsulation frame-relay
 no keepalive
 clock rate 128000
!
interface Serial0/0/0.50 point-to-point
 ip address 1.1.1.1 255.255.255.252
 frame-relay interface-dlci 50
!
interface Serial0/0/0.52 point-to-point
 ip address 2.2.2.1 255.255.255.252
 frame-relay interface-dlci 52

ROUTER2

interface Serial0/0/0
 no ip address
 encapsulation frame-relay
 no keepalive
!
interface Serial0/0/0.50 point-to-point
 ip address 1.1.1.2 255.255.255.252
 frame-relay interface-dlci 50
!
interface Serial0/0/0.52 point-to-point
 ip address 2.2.2.2 255.255.255.252
 frame-relay interface-dlci 52