VLANs between 3 routers

Excuse the noob question but I cannot get around this.

I have the above setup and would like to have router 2 and router 3 access the internet via router 1, but without devices of router 2 having access to devices of router 3.

Router 1 will have a VPN server to let me login from remote and access any device on the network (router 1 or 2 or 3 or any connected devices to them)

Can any of you guide me or point me in the right direction

You need a managed switch, first. See this thread for the reasons.

That said, if the 3 router devices are running OpenWrt or another advanced OS, yes, this is totally possible

Thank you for the pointer. So If the routers are all running openwrt a VLAN trunk between routers cannot be setup? The unmanaged switch will distrupt the tagged packet?

No, this is not what I meant.
YES, the trunking of VLANs between 3 OpenWrt is absolutely possible provided that they are directly connected to each other and/or connected via a managed switch.

This is the problem. Read the post I linked for more info -- sometimes an unmanaged switch will not actually cause any issues, but other times it can cause major problems. It's not worth the risk when managed switches are fairly inexpensive these days.

Thanks again

Will invest in a managed switch and see from there.