Need connect more than devices in one network and all devices see Some of them ?

By network, I assume that OSI Layer 3 is considered.

Check the Vlan of all devices that are connected. Any value of 12 bit i.e. 1-4094 should be same for all devices.

Secondaly, check that network ID in IP address is same for all devices.

Thirdly, the Subnet mask is accurately defined.

Fourthly, the gateway IP is singular and defined as well.

Although, Layer 2 i.e. switch should be working with same vlan id for same network.

Use network switch and VLANs to ,manage secutiy. 

USE SWITCH TO CONNECT DEVICE IN SAME LAN

Devices can be connected thru a Switch.

we should use managed switch with private vlans

we can use router and managable switch for enhance network devices and better speed.

ROUTER IS REQUIRED TO CONNECT MULTIPLE PCS OR DEVICES IN ONE NETWORK.

This can be done by introducing a Layer 3 Device and assignment of IP addreses per Device. We may introdice DNS server( If required) for Name Convention of IP search (Best Pratices for Secure the Network).

with regards,

Diganta 

CCNP/PCI-DSS

We can connect more than a devices using routers and switched and assing an IP adress 

Wifi routers configure through assign ip address and security key,  limited  people can used at time 

check all cables and the ips