You could try the following (I just tried it and it works, though there may be a less cumbersome way):
Open Sentinel and Edit the Profile
Go to the Custom Search tab
Change any of the Custom Search rows to the desired lower and upper search limit, noting the Custom number (which will be Custom 0 to Custom 9 - I used Custom 6).
Go to the Search/Close Call tab
In the Search Key box, change Search Key 1 to be Custom 6
Save the changes to the Profile and write the Profile to the scanner
Begin scanning and press Channel to Hold on a channel
Press Function then 1 to begin searching on Search Key 1
When finished Searching pressFunction+System to resume scanning
You can only do one range at a time, such as 150-170 and when its searching that range, you'll hear everything, not just Federal.
If you want a second range, such as 403-430, you'll have to change a second Custom Search row and assign that to a second Search Key
In the Profile Editor, you can select the Custom Search Tab.
Edit one of those preset searches to change it to the frequency range you want (150 to 170MHz). Then edit a second one for 403 to 430MHz. Note that you can change the names, if you want, to Federal Vhf Search & Federal Uhf Search. (This is basically the same as what ofd001 suggested.)
Now, click on the Scan Selection tab.
Select the Monitor Search with Scan
Click on Options
Set all of the custom search ranges to Avoid except the two you want to use.
Write that to the scanner. That would let you do both at one time.