1) Welcome to the Party!
2) when you post, please post your entire configuration including (but not limited to) your installation method and vicidial version with build.
this IS a requirement for posting along with reading the stickies (at the top of each forum) and the manager's manual (available on EFLO.net, both free and paid versions)
You should also post: Asterisk version, telephony hardware (model number is helpful here), cluster information if you have one, and whether any other software is installed in the box. If your installation method is "from scratch" you must post your operating system and should also post the .iso version from which you installed your original operating system. If your installation is "Hosted" list the site name of the host.
If this is a "Cloud" or "Virtual" server, please note the technology involved along with the version of that techology (ie: VMware Server Version 2.0.2). If it is not, merely stating the Motherboard model # and CPU would be helpful.
Similar to This:
Vicibox X.X from .iso | Vicidial X.X.X-XXX Build XXXXXX-XXXX | Asterisk X.X.X | Single Server | No Digium/Sangoma Hardware | No Extra Software After Installation | Intel DG35EC | Core2Quad Q6600
3) I do note that you mentioned the Vicidial Version with Build, of course, even though you have "GoAutoDial" in front of the version number (a flaw on that particular goautodial .iso which makes it appear as if that's the goautodial version without mention of Vicidial ...). Actually, you have either GoAutoDial 2.0 or 2.1 and VICIDIAL 2.4... so finding out which GoAutoDial and the rest of your information and posting it would be a good idea. (Remember that GoAutoDial is just an installer for Vicidial, just like Vicibox is from Vicibox.com, it's not the actual software).
4) When you say "campaign" and then "if a call arrives", I'm not sure whether you are talking about an inbound call or an outbound call. The reason I mention this is because Inbound calls "arrive" and they do so in 'Ingroups', whereas outbound calls are "made" (?) and they are made FROM Campaigns. Setting a priority for inbound calls is very possible ...
5) The latest version of Vicidial (not compatible with the pretty screens of GoAutodial, I'm afraid, but you can upgrade to it with a goautodial system if you are prepared to lose those screens) has a feature to allow outbound calls to be halted when inbound calls are arriving (so an agent can accept inbound calls and when they "wear off" begin "making" outbound calls autmagically).
So describe your situation a bit more deeply unless something I just said "works" for you. (You can also install Vicibox 4.0.0 on a virtual machine and test it/wander through the menus to see if that would suit your needs ...).